If a decimal has an extra zero at the end, we can remove this extra zero without changing the number.

For example, to find a decimal that's the same as 5.90, we simply remove the zero at the end:

\require{cancel} 5.9\cancel{0} = 5.9

Because 5.90 and 5.9 represent the same decimal number, we say that they are equivalent decimals.

Why does this work? Let's look at the place value chart for 5.90.

ones tenths hundredths
5 . 9 0

We can see that there is a zero in the hundredths column, and there are no smaller place values (for example, there are no thousandths). So, we can remove the hundredths column:

ones tenths
5 . 9

FLAG
Example: Removing a Zero

Simplify 4.90 to its simplest form. What is the equivalent decimal number?

EXPLANATION

To find an equivalent decimal, we remove the zero at the end.

4.9\!\cancel{0} = 4.9

Therefore, 4.90 and 4.9 are equivalent decimals.

FLAG
Practice: Removing a Zero

$23.0=$

a
$0.23$
b
$23$
c
$203$
d
$230$
e
$2.03$
Practice: Removing a Zero

$4.30 =$

a
$4.3$
b
$43$
c
$430$
d
$0.43$
e
$0.043$
Practice: Removing a Zero

$0.040 =$

a
$40$
b
$4$
c
$0.004$
d
$0.04$
e
$0.4$

We're not restricted to removing just one zero to make an equivalent decimal.

For example, to make a decimal that's equivalent to 32.600, we can remove the block of two zeros at the end:

32.6\cancel{00} = 32.6

Similarly, we can make a decimal that's equivalent to 8.000 by removing the block of three zeros:

8.\cancel{000} = 8

Note that after we remove the block of three zeros, there are no more numbers after the decimal place, so we can remove the decimal place as well.

FLAG

Find a decimal that's equivalent to 89.00.

EXPLANATION

To find an equivalent decimal, we remove the zeros at the end.

89.\!\cancel{00} = 89

Therefore, 89.00 and 89 are equivalent decimals.

FLAG

$43.00 =$

a
$43$
b
$0.43$
c
$340$
d
$34$
e
$430$

$357.700 =$

a
$358$
b
$357.7$
c
$350.7$
d
$357$
e
$360.8$

$2.000 =$

a
$0.02$
b
$0.2$
c
$2$
d
$200$
e
$20$

When we attach an extra zero on the right of a decimal, its value stays the same.

For example, 3.2 and 3.20 represent the same number:

3.2 = 3.2{\color{blue}0}

Once again, we say that 3.2 is equivalent to 3.20.

We're not restricted to just one zero. We can attach as many as we'd like! For example, the numbers

3.2{\color{blue}00},\qquad 3.2{\color{blue}000}

are both equivalent to 3.2. They're also equivalent to each other!

We can also find decimals that are equivalent to whole numbers. Let's see an example.

FLAG

Find a decimal that's equivalent to 12.

EXPLANATION

To find an equivalent decimal, we can attach a zero to the end, but only after the decimal point!

12 = 12.{\color{blue}{0}}

Therefore, 12 and 12.0 are equivalent.

FLAG
Practice: Attaching a Zero

$8 =$

a
$0.080$
b
$0.80$
c
$8.0$
d
$80$
e
$800$
Practice: Attaching a Zero

$351.5 =$

a
$3,515$
b
$350$
c
$35.150$
d
$351.50$
e
$355$
Practice: Attaching a Zero

$6.31 = $

a
$6.00$
b
$6.30$
c
$63.1$
d
$6.310$
e
$630$

What is the missing digit in the following equality?

361 = 361 . \fbox{[math]\phantom{0}[/math]} \, 00

EXPLANATION

To find an equivalent decimal, we can add extra zeros to the end.

361 = 361 . \bbox[2px,lightgray]{\color{blue}0} 0 0

Therefore, the missing digit is 0.

FLAG

What is the missing digit in the following equality?

\[ 143.6 = 14 \, \fbox{$\phantom{0}$} .600 \]

a
$4$
b
$6$
c
$0$
d
$3$
e
$1$

$12 =$

a
$12.000$
b
$1.200$
c
$12,000$
d
$0.120$
e
$0.12$
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