21/40 as a Decimal – 0.525 (with Steps)

Q: What is 21/40 as a decimal?

21/40 as a decimal is 0.525. Divide 21 by 40 to get it.

Q: What is 21/40 as a percent?

21/40 is 52.5%: multiply the decimal by 100 (move the decimal point two places to the right).

21/40 as a Decimal

21/40 as a decimal is 0.525 exactly, which is 52.5%.

Result

Answer

\frac{21}{40} = \textcolor{#0b5c56}{0.525}

21/40 as a decimal is 0.525.

Percent: 52.5%

53 of 100 squares ≈ 21/40

Step-by-step solution

The problem

\frac{21}{40}

Divide 21 by 40 (long division). Write down how many times 40 goes in, carry the remainder, add a 0 and divide again. The remainder is 0, so the decimal ends here.

Step	Divide	Digit	Remainder	Working
Whole part	21 ÷ 40	0	21	40 × 0 = 0, 21 − 0 = 21
Decimal place 1	210 ÷ 40	5	10	40 × 5 = 200, 210 − 200 = 10
Decimal place 2	100 ÷ 40	2	20	40 × 2 = 80, 100 − 80 = 20
Decimal place 3	200 ÷ 40	5	0	40 × 5 = 200, 200 − 200 = 0

Read off the decimal. The digits are read from the Digit column.
= 21 \div 40 = \textcolor{#0b5c56}{0.525}
Check with a shortcut. The denominator 40 can be made 1000 by multiplying by 25, so the decimal ends after 3 places.
\frac{21}{40} = \frac{21 \times 25}{40 \times 25} = \frac{525}{1000} = 0.525

All the working together

\begin{aligned} &\frac{21}{40} \\[8pt]  &= 21 \div 40 && \textcolor{#5b6660}{\textsf{divide}} \\[8pt]  &= \textcolor{#0b5c56}{0.525}\end{aligned}

21/40 in other forms

Decimal	0.525
Percent	52.5%
Equivalent fractions	42/80, 63/120, 84/160, 105/200

Why it ends

In lowest terms the denominator is 40 = 2³ × 5. Its only prime factors are 2 and 5 (the factors of 10), so the division comes out exactly and the decimal ends.

Fractions over 40 as decimals

Fraction	Decimal	Percent
1/40	0.025	2.5%
3/40	0.075	7.5%
7/40	0.175	17.5%
9/40	0.225	22.5%
11/40	0.275	27.5%
13/40	0.325	32.5%
17/40	0.425	42.5%
19/40	0.475	47.5%
21/40	0.525	52.5%
23/40	0.575	57.5%
27/40	0.675	67.5%
29/40	0.725	72.5%
31/40	0.775	77.5%
33/40	0.825	82.5%
37/40	0.925	92.5%
39/40	0.975	97.5%

Frequently asked questions

What is 21/40 as a decimal?

21/40 as a decimal is 0.525. Divide 21 by 40 to get it.

What is 21/40 as a percent?

21/40 is 52.5%: multiply the decimal by 100 (move the decimal point two places to the right).

Is 21/40 a terminating or a repeating decimal?

Terminating – the digits stop. In lowest terms the denominator is 40 = 2³ × 5. Its only prime factors are 2 and 5 (the factors of 10), so the division comes out exactly and the decimal ends.

More fractions as decimals

Any other fraction: use the Fraction to Decimal Calculator, or see every fraction to sixteenths on the printable fraction chart.