We can find a good estimate for the sum of two decimals by first rounding each decimal to the nearest whole number.
To illustrate, let's find an estimate for the value of
First, we round both numbers to the nearest whole number:
Then, we calculate the sum:
Therefore, is about
The exact answer is so our estimate is pretty close.
Estimate by rounding each number to the nearest whole number.
First, we round both numbers to the nearest whole number:
Next, we calculate the sum:
Therefore, is about
By rounding each number to the nearest whole number, estimate the value of $22.75 + 5.43.$
|
a
|
$25$ |
|
b
|
$27$ |
|
c
|
$20$ |
|
d
|
$30$ |
|
e
|
$28$ |
By rounding each number to the nearest whole number, estimate the value of $2.7 + 5.4.$
|
a
|
$9$ |
|
b
|
$15$ |
|
c
|
$7$ |
|
d
|
$8$ |
|
e
|
$6$ |
Joe cuts a piece of wire into two lengths. One part is meters long, and the other part is meters long. By rounding each number to the nearest whole number, estimate the length of the wire before Joe cut it.
To estimate the initial length of the wire, we need to estimate the sum
First, we round both numbers to the nearest whole number:
Next, we calculate the sum:
Therefore, the length of the wire was approximately meters before Joe cut it.
Lisa has two piggy banks. She's saved $\$23.90$ in one and $\$19.25$ in the other. By rounding each number to the nearest dollar, estimate how much Lisa saved in total.
|
a
|
$\$43$ |
|
b
|
$\$42$ |
|
c
|
$\$45$ |
|
d
|
$\$41$ |
|
e
|
$\$44$ |
Barbara buys $5.45$ pounds of apples and $2.87$ pounds of plums. By rounding each number to the nearest whole number, estimate the total weight of the fruits that Barbara purchased.
|
a
|
$8$ pounds |
|
b
|
$7$ pounds |
|
c
|
$9$ pounds |
|
d
|
$6$ pounds |
|
e
|
$15$ pounds |
We also use rounding to estimate the difference of two decimals. To illustrate, let's find an estimate of
First, we round both numbers to the nearest whole number:
Then, we calculate the difference:
Therefore, is about
By rounding each number to the nearest whole number, estimate the value of
First, we round both numbers to the nearest whole number:
Next, we calculate the difference:
Therefore, is approximately
Estimate $29.85- 2.32$ by rounding each number to the nearest whole number.
|
a
|
$28$ |
|
b
|
$2$ |
|
c
|
$25$ |
|
d
|
$27$ |
|
e
|
$29$ |
Estimate $28.6 - 23.3$ by rounding each number to the nearest whole number.
|
a
|
$11$ |
|
b
|
$25$ |
|
c
|
$5$ |
|
d
|
$3$ |
|
e
|
$6$ |
A meteorologist measures the total amount of rainfall that two cities, city and city , received in a week. He found that both cities received a combined total of inches of rain. If city received inches of rain, then by rounding each number to the nearest whole number, estimate the amount of rainfall that city received.
To estimate the total amount of rain that city received, we need to estimate the difference
First, we round both numbers to the nearest whole number:
Next, we calculate the difference:
Therefore, city received approximately inches of rainfall during the week.
Peter had a lunch that contained some french fries. The lunch contained $100.79$ calories in total. If the fries alone contained $70.75$ calories, then by rounding each decimal to the nearest whole number, estimate how many calories were in the rest of his lunch.
|
a
|
$28$ calories |
|
b
|
$30$ calories |
|
c
|
$24$ calories |
|
d
|
$33$ calories |
|
e
|
$32$ calories |
Brad joined two pieces of wire together to make a wire that was $17.2$ meters long. If the first piece of wire was $7.8$ meters long, then by rounding each number to the nearest whole number, estimate the length of the second piece of wire.
|
a
|
$7$ meters |
|
b
|
$8$ meters |
|
c
|
$10$ meters |
|
d
|
$11$ meters |
|
e
|
$9$ meters |