We can use place value to subtract two-digit whole numbers easily.
As an example, let's find the following difference:
65-42
First, we line up our numbers (ones over ones and tens over tens ):
Tens
Ones
\color{red}6
\color{blue}5
\color{red}4
\color{blue}2
Next, we proceed by subtracting the numbers in each place value (from right to left) and writing the results below:
Step 1. Subtracting the ones, we get
{\color{blue}5} - {\color{blue}2} = {\color{blue}3}{:}
Tens
Ones
\color{red}6
\color{blue}5
\color{red}4
\color{blue}2
\color{blue}3
Step 2. Subtracting the tens, we get
{\color{red}6} - {\color{red}4} = {\color{red}2}{:}
Tens
Ones
\color{red}6
\color{blue}5
\color{red}4
\color{blue}2
\color{red}2
\color{blue}3
Therefore, we conclude that
65-42 = 23.
Drawing place value charts each time we want to subtract a pair of numbers isn't very convenient. For this reason, we usually follow a simplified process called the standard algorithm .
Let's once again consider the following difference:
65-42
First, we line up our numbers as follows: (ones over ones, and tens over tens):
\begin{array}{cccccccc}
& & \!\!\!\! 6 \!\!\!\!& \!\!\!\! 5 \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 4 \!\!\!\!& \!\!\!\! 2 \!\!\!\! \\
\hline
& & & &
\end{array}
Next, we proceed by subtracting the numbers in each place value (from right to left):
Step 1. Subtracting the ones, we get
{\color{blue}5} - {\color{blue}2} = {\color{blue}3}{:}
\begin{array}{cccccccc}
& & \!\!\!\! 6 \!\!\!\!& \!\!\!\! {\color{blue}5} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 4 \!\!\!\!& \!\!\!\! {\color{blue}2} \!\!\!\! \\
\hline
& & \!\!\!\! \!\!\!\!& \!\!\!\! {\color{blue}3} \!\!\!\!
\end{array}
Step 2. Subtracting the tens, we get
{\color{red}6 } - {\color{red}4} = {\color{red}2}{:}
\begin{array}{cccccccc}
& & \!\!\!\! {\color{red}6} \!\!\!\!& \!\!\!\! 5 \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! {\color{red}4} \!\!\!\!& \!\!\!\! 2 \!\!\!\! \\
\hline
& & \!\!\!\! {\color{red}2} \!\!\!\!& \!\!\!\! 3 \!\!\!\!
\end{array}
Therefore,
65 - 42 = 23.
Find the value of
84 - 31.
First, we line up our numbers (ones over ones and tens over tens ):
\begin{array}{cccccccc}
& & \!\!\!\! 8 \!\!\!\!& \!\!\!\! 4 \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 3 \!\!\!\!& \!\!\!\! 1 \!\!\!\! \\
\hline
& & & &
\end{array}
Next, we proceed by subtracting the numbers in each place value (from right to left):
Step 1. Subtracting the ones,
{\color{blue}4} - {\color{blue}1} = {\color{blue}3}{:}
\begin{array}{cccccccc}
& & \!\!\!\! 8 \!\!\!\!& \!\!\!\! {\color{blue}4} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 3 \!\!\!\!& \!\!\!\! {\color{blue}1} \!\!\!\! \\
\hline
& & \!\!\!\! \!\!\!\!& \!\!\!\! {\color{blue}3} \!\!\!\!
\end{array}
Step 2. Subtracting the tens,
{\color{blue}8 } - {\color{blue}3} = {\color{blue}5}{:}
\begin{array}{cccccccc}
& & \!\!\!\! {\color{blue}8} \!\!\!\!& \!\!\!\! 4 \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! {\color{blue}3} \!\!\!\!& \!\!\!\! 1 \!\!\!\! \\
\hline
& & \!\!\!\! {\color{blue}5} \!\!\!\!& \!\!\!\! 3 \!\!\!\!
\end{array}
Therefore,
84 - 31 = 53.
First, we line up our numbers (ones over ones and tens over tens ):
\[
\begin{array}{cccccccc}
& & \!\!\!\! 2 \!\!\!\! & \!\!\!\! 5 \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 2 \!\!\!\!& \!\!\!\! 2 \!\!\!\! \\
\hline
& & & &
\end{array}
\]
Next, we proceed by subtracting the numbers in each place value (from right to left):
Step 1. Subtracting the ones, ${\color{blue}5} - {\color{blue}2} = {\color{blue}3}{:}$
\[
\begin{array}{cccccccc}
& & \!\!\!\! 2 \!\!\!\!& \!\!\!\! {\color{blue}5} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 2 \!\!\!\!& \!\!\!\! {\color{blue}2} \!\!\!\! \\
\hline
& & \!\!\!\! \!\!\!\!& \!\!\!\! {\color{blue}3} \!\!\!\! &
\end{array}
\]
Step 2. Subtracting the tens, ${\color{blue}2 } - {\color{blue}2} = {\color{blue}0}{:}$
\[
\begin{array}{cccccccc}
& & \!\!\!\! {\color{blue}2} \!\!\!\!& \!\!\!\! 5 \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! {\color{blue}2} \!\!\!\!& \!\!\!\! 2 \!\!\!\! \\
\hline
& & \!\!\!\! {\color{blue}0} \!\!\!\!& \!\!\!\! 3 \!\!\!\! &
\end{array}
\]
Therefore, $25 - 22 = \bbox[3pt,Gainsboro]{\color{blue}3}.$
a
$13$
b
$27$
c
$23$
d
$17$
e
$7$
First, we line up our numbers (ones over ones and tens over tens ):
\[
\begin{array}{cccccccc}
& & \!\!\!\! 5 \!\!\!\!& \!\!\!\! 8 \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 4 \!\!\!\!& \!\!\!\! 5 \!\!\!\! \\
\hline
& & & &
\end{array}
\]
Next, we proceed by subtracting the numbers in each place value (from right to left):
Step 1. Subtracting the ones, ${\color{blue}8} - {\color{blue}5} = {\color{blue}3}{:}$
\[
\begin{array}{cccccccc}
& & \!\!\!\! 5 \!\!\!\!& \!\!\!\! {\color{blue}8} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 4 \!\!\!\!& \!\!\!\! {\color{blue}5} \!\!\!\! \\
\hline
& & \!\!\!\! \!\!\!\!& \!\!\!\! {\color{blue}3} \!\!\!\!
\end{array}
\]
Step 2. Subtracting the tens, ${\color{blue}5 } - {\color{blue}4} = {\color{blue}1}{:}$
\[
\begin{array}{cccccccc}
& & \!\!\!\! {\color{blue}5} \!\!\!\!& \!\!\!\! 8 \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! {\color{blue}4} \!\!\!\!& \!\!\!\! 5 \!\!\!\! \\
\hline
& & \!\!\!\! {\color{blue}1} \!\!\!\!& \!\!\!\! 3 \!\!\!\!
\end{array}
\]
Therefore, $58 - 45 = 13.$
a
$11$
b
$21$
c
$19$
d
$29$
e
$12$
First, we line up our numbers (ones over ones and tens over tens ):
\[
\begin{array}{cccccccc}
& & \!\!\!\! 5 \!\!\!\!& \!\!\!\! 5 \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 3 \!\!\!\!& \!\!\!\! 4 \!\!\!\! \\
\hline
& & & &
\end{array}
\]
Next, we proceed by subtracting the numbers in each place value (from right to left):
Step 1. Subtracting the ones, ${\color{blue}5} - {\color{blue}4} = {\color{blue}1}{:}$
\[
\begin{array}{cccccccc}
& & \!\!\!\! 5 \!\!\!\!& \!\!\!\! {\color{blue}5} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 3 \!\!\!\!& \!\!\!\! {\color{blue}4} \!\!\!\! \\
\hline
& & \!\!\!\! \!\!\!\!& \!\!\!\! {\color{blue}1} \!\!\!\!
\end{array}
\]
Step 2. Subtracting the tens, ${\color{blue}5 } - {\color{blue}3} = {\color{blue}2}{:}$
\[
\begin{array}{cccccccc}
& & \!\!\!\! {\color{blue}5} \!\!\!\!& \!\!\!\! 5 \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! {\color{blue}3} \!\!\!\!& \!\!\!\! 4 \!\!\!\! \\
\hline
& & \!\!\!\! {\color{blue}2} \!\!\!\!& \!\!\!\! 1 \!\!\!\!
\end{array}
\]
Therefore, $55 - 34 = 21.$
Let's consider the following subtraction problem:
45-17
First, we line up our numbers (ones over ones and tens over tens), as before:
Tens
Ones
\color{red}4
\color{blue}5
1
7
We have a problem. Since
5
is smaller than
7,
we cannot calculate
5-7.
So what do we do?
The answer is to take the first number
({\color{red}{4}}{\color{blue}{5}}),
"borrow" a ten from the tens place and put it in the ones place, as follows:
\begin{align*}
{\color{red}{4}}\, \textrm{tens} + {\color{blue}{5}}\,\textrm{ones}
&= {\color{red}{3}}\, \textrm{tens} + {\color{blue}{15}}\,\textrm{ones}
\end{align*}
Updating the first row in our table gives the following:
Tens
Ones
\color{red}3
\color{blue}15
1
7
Now, we subtract as usual!
Step 1. Subtracting the ones, we get
15-7=8{:}
Tens
Ones
\color{red}3
\color{blue}15
1
7
8
Step 1. Subtracting the tens, we get
3-1=2{:}
Tens
Ones
\color{red}3
\color{blue}15
1
7
2
8
Therefore, we conclude that
45-17 = 28.
Let's now solve the same problem using the standard algorithm.
Once again, we consider the following difference:
45 - 17
To use the standard algorithm, we first line up our numbers (ones over ones and tens over tens):
\begin{array}{cccccccc}
& & \!\!\!\! 4 \!\!\!\!& \!\!\!\! 5 \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 1 \!\!\!\!& \!\!\!\! 7 \!\!\!\! \\
\hline
& & & &
\end{array}
Step 1. We cannot compute
5-7.
So, we borrow
1
from the tens place. Then we have
4 - 1 = {\color{red}3}
tens and
\color{red}15
ones:
\require{cancel}
\begin{array}{cccccccc}
& & \!\!\!\! \small{\color{red}3} \!\!\!& \!\!\! \small{\color{red}15} \!\!\!\! \\
& & \!\!\!\! \cancel{4} \!\!\!& \!\!\! \cancel{5} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 1 \!\!\!& \!\!\! 7 \!\!\!\! \\
\hline
& & \!\!\!\! \!\!\!& \!\!\! \!\!\!\!
\end{array}
Subtracting the ones, we get
{\color{blue}15} - {\color{blue}7} = {\color{blue}8}{:}
\begin{array}{cccccccc}
& & \!\!\!\! \small{3} \!\!\!& \!\!\! \small{\color{blue}15} \!\!\!\! \\
& & \!\!\!\! \cancel{4} \!\!\!& \!\!\! \cancel{5} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 1 \!\!\!& \!\!\! {\color{blue}7} \!\!\!\! \\
\hline
& & \!\!\!\! \!\!\!& \!\!\! {\color{blue}8} \!\!\!\!
\end{array}
Step 2. Subtracting the tens, we get
{\color{blue}3} - {\color{blue}1} = {\color{blue}2}{:}
\begin{array}{cccccccc}
& & \!\!\!\! \small{\color{blue}3} \!\!\!& \!\!\! \small{15} \!\!\!\! \\
& & \!\!\!\! \cancel{4} \!\!\!& \!\!\! \cancel{5} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! {\color{blue}1} \!\!\!& \!\!\! 7 \!\!\!\! \\
\hline
& & \!\!\!\! {\color{blue}2} \!\!\!& \!\!\! 8 \!\!\!\!
\end{array}
Therefore,
45 - 17 = 28.
Find the value of
72 - 56.
First, we line up our numbers (ones over ones and tens over tens ):
\begin{array}{cccccccc}
& & \!\!\!\! 7 \!\!\!\!& \!\!\!\! 2 \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 5 \!\!\!\!& \!\!\!\! 6 \!\!\!\! \\
\hline
& & & &
\end{array}
Next, we proceed by subtracting the numbers in each place value (from right to left):
Step 1. We cannot compute
2 - 6.
So, we borrow
1
from the tens place. Then we have
7 - 1 = {\color{red}6}
tens and
\color{red}12
ones:
\require{cancel}
\begin{array}{cccccccc}
& & \!\!\!\! \small{\color{red}6} \!\!\!& \!\!\! \small{\color{red}12} \!\!\!\! \\
& & \!\!\!\! \cancel{7} \!\!\!& \!\!\! \cancel{2} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 5 \!\!\!& \!\!\! 6 \!\!\!\! \\
\hline
& & \!\!\!\! \!\!\!& \!\!\! \!\!\!\!
\end{array}
Now, subtracting the ones,
{\color{blue}12} - {\color{blue}6} = {\color{blue}6}{:}
\begin{array}{cccccccc}
& & \!\!\!\! \small{6} \!\!\!& \!\!\! \small{\color{blue}12} \!\!\!\! \\
& & \!\!\!\! \cancel{7} \!\!\!& \!\!\! \cancel{2} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 5 \!\!\!& \!\!\! {\color{blue}6} \!\!\!\! \\
\hline
& & \!\!\!\! \!\!\!& \!\!\! {\color{blue}6} \!\!\!\!
\end{array}
Step 2. Subtracting the tens,
{\color{blue}6} - {\color{blue}5} = {\color{blue}1}{:}
\begin{array}{cccccccc}
& & \!\!\!\! \small{\color{blue}6} \!\!\!& \!\!\! \small{12} \!\!\!\! \\
& & \!\!\!\! \cancel{7} \!\!\!& \!\!\! \cancel{2} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! {\color{blue}5} \!\!\!& \!\!\! 6 \!\!\!\! \\
\hline
& & \!\!\!\! {\color{blue}1} \!\!\!& \!\!\! 6 \!\!\!\!
\end{array}
Therefore,
72 - 56 = 16.
First, we line up our numbers (ones over ones and tens over tens ):
\[
\begin{array}{cccccccc}
& & \!\!\!\! 5 \!\!\!\!& \!\!\!\! 6 \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 3 \!\!\!\!& \!\!\!\! 9 \!\!\!\! \\
\hline
& & & &
\end{array}
\]
Next, we proceed by subtracting the numbers in each place value (from right to left):
Step 1. We cannot compute $6 - 9.$ So, we borrow $1$ from the tens place. Then we have $5 - 1 = {\color{red}4}$ tens and $\color{red}16$ ones:
\[
\require{cancel}
\begin{array}{cccccccc}
& & \!\!\!\! \small{\color{red}4} \!\!\!& \!\!\! \small{\color{red}16} \!\!\!\! \\
& & \!\!\!\! \cancel{5} \!\!\!& \!\!\! \cancel{6} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 3 \!\!\!& \!\!\! 9 \!\!\!\! \\
\hline
& & \!\!\!\! \!\!\!& \!\!\! \!\!\!\! &
\end{array}
\]
Now, subtracting the ones, ${\color{blue}16} - {\color{blue}9} = {\color{blue}7}{:}$
\[
\begin{array}{cccccccc}
& & \!\!\!\! \small{4} \!\!\!& \!\!\! \small{\color{blue}16} \!\!\!\! \\
& & \!\!\!\! \cancel{5} \!\!\!& \!\!\! \cancel{6} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 3 \!\!\!& \!\!\! {\color{blue}9} \!\!\!\! \\
\hline
& & \!\!\!\! \!\!\!& \!\!\! {\color{blue}7} \!\!\!\! &
\end{array}
\]
Step 2. Subtracting the tens, ${\color{blue}4} - {\color{blue}3} = {\color{blue}1}{:}$
\[
\begin{array}{cccccccc}
& & \!\!\!\! \small{\color{blue}4} \!\!\!& \!\!\! \small{16} \!\!\!\! \\
& & \!\!\!\! \cancel{5} \!\!\!& \!\!\! \cancel{6} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! {\color{blue}3} \!\!\!& \!\!\! 9 \!\!\!\! \\
\hline
& & \!\!\!\! {\color{blue}1} \!\!\!& \!\!\! 7 \!\!\!\! &
\end{array}
\]
Therefore, $56 - 39 = \bbox[3pt,Gainsboro]{\color{blue}17}.$
a
$37$
b
$23$
c
$33$
d
$17$
e
$13$
First, we line up our numbers (ones over ones and tens over tens ):
\[
\begin{array}{cccccccc}
& & \!\!\!\! 8 \!\!\!\!& \!\!\!\! 6 \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 6 \!\!\!\!& \!\!\!\! 9 \!\!\!\! \\
\hline
& & & &
\end{array}
\]
Next, we proceed by subtracting the numbers in each place value (from right to left):
Step 1. We cannot compute $6 - 9.$ So, we borrow $1$ from the tens place. Then we have $8 - 1 = {\color{red}7}$ tens and $\color{red}16$ ones:
\[
\require{cancel}
\begin{array}{cccccccc}
& & \!\!\!\! \small{\color{red}7} \!\!\!& \!\!\! \small{\color{red}16} \!\!\!\! \\
& & \!\!\!\! \cancel{8} \!\!\!& \!\!\! \cancel{6} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 6 \!\!\!& \!\!\! 9 \!\!\!\! \\
\hline
& & \!\!\!\! \!\!\!& \!\!\! \!\!\!\!
\end{array}
\]
Now, subtracting the ones, ${\color{blue}16} - {\color{blue}9} = {\color{blue}7}{:}$
\[
\begin{array}{cccccccc}
& & \!\!\!\! \small{7} \!\!\!& \!\!\! \small{\color{blue}16} \!\!\!\! \\
& & \!\!\!\! \cancel{8} \!\!\!& \!\!\! \cancel{6} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 6 \!\!\!& \!\!\! {\color{blue}9} \!\!\!\! \\
\hline
& & \!\!\!\! \!\!\!& \!\!\! {\color{blue}7} \!\!\!\!
\end{array}
\]
Step 2. Subtracting the tens, ${\color{blue}7} - {\color{blue}6} = {\color{blue}1}{:}$
\[
\begin{array}{cccccccc}
& & \!\!\!\! \small{\color{blue}7} \!\!\!& \!\!\! \small{16} \!\!\!\! \\
& & \!\!\!\! \cancel{8} \!\!\!& \!\!\! \cancel{6} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! {\color{blue}6} \!\!\!& \!\!\! 9 \!\!\!\! \\
\hline
& & \!\!\!\! {\color{blue}1} \!\!\!& \!\!\! 7 \!\!\!\!
\end{array}
\]
Therefore, $86 - 69 = 17.$
First, we line up our numbers (ones over ones and tens over tens ):
\[
\begin{array}{cccccccc}
& & \!\!\!\! 9 \!\!\!\!& \!\!\!\! 4 \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 3 \!\!\!\!& \!\!\!\! 5 \!\!\!\! \\
\hline
& & & &
\end{array}
\]
Next, we proceed by subtracting the numbers in each place value (from right to left):
Step 1. We cannot compute $4 - 5.$ So, we borrow $1$ from the tens place. Then we have $9 - 1 = {\color{red}8}$ tens and $\color{red}14$ ones:
\[
\require{cancel}
\begin{array}{cccccccc}
& & \!\!\!\! \small{\color{red}8} \!\!\!& \!\!\! \small{\color{red}14} \!\!\!\! \\
& & \!\!\!\! \cancel{9} \!\!\!& \!\!\! \cancel{4} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 3 \!\!\!& \!\!\! 5 \!\!\!\! \\
\hline
& & \!\!\!\! \!\!\!& \!\!\! \!\!\!\! &
\end{array}
\]
Now, subtracting the ones, ${\color{blue}14} - {\color{blue}5} = {\color{blue}9}{:}$
\[
\begin{array}{cccccccc}
& & \!\!\!\! \small{8} \!\!\!& \!\!\! \small{\color{blue}14} \!\!\!\! \\
& & \!\!\!\! \cancel{9} \!\!\!& \!\!\! \cancel{4} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 3 \!\!\!& \!\!\! {\color{blue}5} \!\!\!\! \\
\hline
& & \!\!\!\! \!\!\!& \!\!\! {\color{blue}9} \!\!\!\! &
\end{array}
\]
Step 2. Subtracting the tens, ${\color{blue}8} - {\color{blue}3} = {\color{blue}5}{:}$
\[
\begin{array}{cccccccc}
& & \!\!\!\! \small{\color{blue}8} \!\!\!& \!\!\! \small{14} \!\!\!\! \\
& & \!\!\!\! \cancel{9} \!\!\!& \!\!\! \cancel{4} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! {\color{blue}3} \!\!\!& \!\!\! 5 \!\!\!\! \\
\hline
& & \!\!\!\! {\color{blue}5} \!\!\!& \!\!\! 9 \!\!\!\! &
\end{array}
\]
Therefore, $94 - 35 = \bbox[3pt,Gainsboro]{\color{blue}59}.$
A college basketball team scored
25
fewer points this month compared to last month. If they scored
82
points last month, how many points did they score this month?
To find the number of points the team scored this month, we need to find
82-25.
First, we line up our numbers (ones over ones and tens over tens ):
\begin{array}{cccccccc}
& & \!\!\!\! 8 \!\!\!\!& \!\!\!\! 2 \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 2 \!\!\!\!& \!\!\!\! 5 \!\!\!\! \\
\hline
& & & &
\end{array}
Next, we proceed by subtracting the numbers in each place value (from right to left):
Step 1. We cannot compute
2 - 5.
So, we borrow
1
from the tens place. Then we have
8 - 1 = {\color{red}7}
tens and
\color{red}12
ones:
\require{cancel}
\begin{array}{cccccccc}
& & \!\!\!\! \small{\color{red}7} \!\!\!& \!\!\! \small{\color{red}12} \!\!\!\! \\
& & \!\!\!\! \cancel{8} \!\!\!& \!\!\! \cancel{2} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 2 \!\!\!& \!\!\! 5 \!\!\!\! \\
\hline
& & \!\!\!\! \!\!\!& \!\!\! \!\!\!\!
\end{array}
Now, subtracting the ones,
{\color{blue}12} - {\color{blue}5} = {\color{blue}7}{:}
\begin{array}{cccccccc}
& & \!\!\!\! \small{7} \!\!\!& \!\!\! \small{\color{blue}12} \!\!\!\! \\
& & \!\!\!\! \cancel{8} \!\!\!& \!\!\! \cancel{2} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 2 \!\!\!& \!\!\! {\color{blue}5} \!\!\!\! \\
\hline
& & \!\!\!\! \!\!\!& \!\!\! {\color{blue}7} \!\!\!\!
\end{array}
Step 2. Subtracting the tens,
{\color{blue}7} - {\color{blue}2} = {\color{blue}5}{:}
\begin{array}{cccccccc}
& & \!\!\!\! \small{\color{blue}7} \!\!\!& \!\!\! \small{12} \!\!\!\! \\
& & \!\!\!\! \cancel{8} \!\!\!& \!\!\! \cancel{2} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! {\color{blue}2} \!\!\!& \!\!\! 5 \!\!\!\! \\
\hline
& & \!\!\!\! {\color{blue}5} \!\!\!& \!\!\! 7 \!\!\!\!
\end{array}
Therefore, the team scored
57
points last month.
Angie is reading a book with $74$ pages. So far, she has read $31$ pages. How many pages does Angie have left to read?
a
$47$ pages
b
$27$ pages
c
$43$ pages
d
$37$ pages
e
$33$ pages
To find how many pages Angie has left to read, we need to find $74-31.$
First, we line up our numbers (ones over ones and tens over tens ):
\[
\begin{array}{cccccccc}
& & \!\!\!\! 7 \!\!\!\!& \!\!\!\! 4 \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 3 \!\!\!\!& \!\!\!\! 1 \!\!\!\! \\
\hline
& & & &
\end{array}
\]
Next, we proceed by subtracting the numbers in each place value (from right to left):
Step 1. Subtracting the ones, ${\color{blue}4} - {\color{blue}1} = {\color{blue}3}{:}$
\[
\begin{array}{cccccccc}
& & \!\!\!\! 7 \!\!\!\!& \!\!\!\! {\color{blue}4} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 3 \!\!\!\!& \!\!\!\! {\color{blue}1} \!\!\!\! \\
\hline
& & \!\!\!\! \!\!\!\!& \!\!\!\! {\color{blue}3} \!\!\!\!
\end{array}
\]
Step 2. Subtracting the tens, ${\color{blue}7 } - {\color{blue}3} = {\color{blue}4}{:}$
\[
\begin{array}{cccccccc}
& & \!\!\!\! {\color{blue}7} \!\!\!\!& \!\!\!\! 4 \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! {\color{blue}3} \!\!\!\!& \!\!\!\! 1 \!\!\!\! \\
\hline
& & \!\!\!\! {\color{blue}4} \!\!\!\!& \!\!\!\! 3 \!\!\!\!
\end{array}
\]
Therefore Ange has $43$ pages left to read.
Pam bought $36$ candies for Halloween. During the day, $18$ trick-or-treaters knocked on her door. Given that each trick-or-treater receives one candy each, how many candies does Pam have remaining?
a
$12$ candies
b
$18$ candies
c
$14$ candies
d
$22$ candies
e
$16$ candies
To find how many candies Pam has remaining, we need to find $36-18.$
First, we line up our numbers (ones over ones and tens over tens ):
\[
\begin{array}{cccccccc}
& & \!\!\!\! 3 \!\!\!\!& \!\!\!\! 6 \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 1 \!\!\!\!& \!\!\!\! 8 \!\!\!\! \\
\hline
& & & &
\end{array}
\]
Next, we proceed by subtracting the numbers in each place value (from right to left):
Step 1. We cannot compute $6 - 8.$ So, we borrow $1$ from the tens place. Then, we have $3 - 1 = {\color{red}2}$ tens and $\color{red}16$ ones:
\[
\require{cancel}
\begin{array}{cccccccc}
& & \!\!\!\! \small{\color{red}2} \!\!\!& \!\!\! \small{\color{red}16} \!\!\!\! \\
& & \!\!\!\! \cancel{3} \!\!\!& \!\!\! \cancel{6} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 1 \!\!\!& \!\!\! 8 \!\!\!\! \\
\hline
& & \!\!\!\! \!\!\!& \!\!\! 8 \!\!\!\!
\end{array}
\]
Now, subtracting the ones, ${\color{blue}16} - {\color{blue}8} = {\color{blue}8}{:}$
\[
\begin{array}{cccccccc}
& & \!\!\!\! \small{2} \!\!\!& \!\!\! \small{\color{blue}16} \!\!\!\! \\
& & \!\!\!\! \cancel{3} \!\!\!& \!\!\! \cancel{6} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! 1 \!\!\!& \!\!\! {\color{blue}8} \!\!\!\! \\
\hline
& & \!\!\!\! \!\!\!& \!\!\! {\color{blue}8} \!\!\!\!
\end{array}
\]
Step 2. Subtracting the tens, ${\color{blue}2} - {\color{blue}1} = {\color{blue}1}{:}$
\[
\begin{array}{cccccccc}
& & \!\!\!\! \small{\color{blue}2} \!\!\!& \!\!\! \small{16} \!\!\!\! \\
& & \!\!\!\! \cancel{3} \!\!\!& \!\!\! \cancel{6} \!\!\!\! \\
\!\!\!\!-\!\!\!\! & & \!\!\!\! {\color{blue}1} \!\!\!& \!\!\! 8 \!\!\!\! \\
\hline
& & \!\!\!\! {\color{blue}1} \!\!\!& \!\!\! 8 \!\!\!\!
\end{array}
\]
Therefore Pam has $18$ candies remaining.
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