Sometimes a number cannot be shared into equal groups exactly — a little is left over. The amount left over is called the remainder.
Example. Share $13$ sweets among $4$ children. Each child gets $3$ (that uses $12$ sweets), and $1$ sweet is left over. We write this as:
$$13\div4 = 3 \text{ remainder } 1\quad(\text{short: } 3\text{ r }1)$$
Here $3$ is the quotient (how many each got) and $1$ is the remainder (what was left).
The most important rule: the remainder is always smaller than the divisor. If the remainder were as big as the divisor, you could give out one more to each group.
How to check your answer. Use:
$$\text{quotient}\times\text{divisor}+\text{remainder}=\text{dividend}$$
For $13\div4=3\text{ r }1$: $3\times4+1=13$ — correct!
When the remainder is $0$. If nothing is left over, the number divides exactly. For example $12\div4=3$ with remainder $0$.
Common mistakes to avoid:
- Leaving a remainder that is equal to or bigger than the divisor (it must be smaller).
- Forgetting the remainder when the sharing is not exact.