Dividing Decimals by Whole Numbers

Dividing a decimal by a whole number works almost exactly like regular long division. The most important rule to remember is placing the decimal point in your answer (the quotient) correctly.

The Golden Rule

When you set up your long division, place the decimal point in the quotient directly above the decimal point in the dividend (the number you are dividing). Once the decimal point is placed, you just divide normally!

Step-by-Step Examples

Example 1: $15.5 \div 5$

1. Look at the whole number part: $5$ goes into $15$ exactly $3$ times.
2. Place the decimal point in the quotient directly above the decimal in $15.5$.
3. Bring down the $5$. Then, $5$ goes into $5$ exactly $1$ time.
4. Answer: $3.1$

Example 2: $7.56 \div 4$

1. $4$ goes into $7$ one time ($1$). Subtract $4$ from $7$ to get a remainder of $3$.
2. Place the decimal point in the quotient directly above the one in $7.56$.
3. Bring down the $5$ to make $35$. $4$ goes into $35$ eight times ($4 \times 8 = 32$). The remainder is $3$.
4. Bring down the $6$ to make $36$. $4$ goes into $36$ exactly nine times ($4 \times 9 = 36$).
5. Answer: $1.89$

Adding Zeros

Sometimes, you might reach the end of the number and still have a remainder. Because you are working with decimals, you can simply add a $0$ to the end of the dividend and keep dividing. Adding zeros to the end of a decimal does not change its value (for example, $3.5$ is the same as $3.50$).

Example 3: $0.936 \div 12$

1. $12$ goes into $0$ zero times. Place your decimal point.
2. $12$ goes into $9$ zero times. Write a $0$ in the quotient.
3. Now look at $93$. $12$ goes into $93$ seven times ($12 \times 7 = 84$). Subtract to get a remainder of $9$.
4. Bring down the $6$ to make $96$. $12$ goes into $96$ exactly eight times ($12 \times 8 = 96$).
5. Answer: $0.078$