You can divide whole numbers and you can work with tenths and hundredths. Dividing a decimal by a whole number is fair sharing, with tenths and hundredths shared just like ones.
Idea clave
Divide as with whole numbers, and put the decimal point in the quotient straight above the point in the dividend. If the division does not come out even, write zeros after the last digit and keep going.
Por qué funciona
Sharing $6.3$ among 3 is sharing 6 ones and 3 tenths: each person gets 2 ones and 1 tenth, $2.1$. Thinking in the smallest unit helps: $9.36$ is 936 hundredths, and $936 \div 4 = 234$ hundredths, which is $2.34$. A zero at the end, $3.4 = 3.40$, adds no value but gives you hundredths to share.
Worked examples
Ejemplo resuelto: Share ones and tenths
Find $6.3 \div 3$.
- 6 ones $\div 3 = 2$ ones.
- 3 tenths $\div 3 = 1$ tenth.
Respuesta: $2.1$
Ejemplo resuelto: Long division with a point
Find $9.36 \div 4$.
- $9 \div 4 = 2$ with 1 left over. Write 2, then the point above the point.
- Bring down the 3: 13 tenths. $13 \div 4 = 3$ with 1 left over.
- Bring down the 6: 16 hundredths. $16 \div 4 = 4$.
- Check: $2.34 \times 4 = 9.36$.
Respuesta: $2.34$
Ejemplo resuelto: Write a zero to keep going
Find $3.4 \div 4$.
- 4 does not go into 3 ones, so write 0 ones and the point.
- 34 tenths $\div 4 = 8$ with 2 tenths left.
- Write $3.4$ as $3.40$: the 2 tenths become 20 hundredths. $20 \div 4 = 5$.
Respuesta: $0.85$
Error común
Losing the decimal point and writing $9.36 \div 4 = 234$ or $23.4$. Check with an estimate: $9 \div 4$ is a little more than 2, so the answer is $2.34$.