Make sure the foundations are solid
Long division leans on three earlier skills: times tables, subtraction with regrouping, and place value. If any of these is shaky, fix it first, otherwise long division will feel impossible no matter how clearly you explain the steps.
Use the divide,multiply,subtract,bring down cycle
Every step of long division is the same four moves, repeated: Divide, Multiply, Subtract, Bring down. Many teachers use a mnemonic (Does McDonald's Sell Burgers?) so children remember the order.
- Divide: how many times does the divisor go into the current digits?
- Multiply: that answer times the divisor.
- Subtract: take it away to find the remainder so far.
- Bring down: the next digit, and repeat.
Start small, then scale up
Begin with no remainders and a single-digit divisor. Once the cycle is automatic, add remainders, then larger numbers, then decimals. Keep the divisor small while the method is new.
Common mistakes
- Forgetting to bring the next digit down.
- Misaligning digits so place value goes wrong.
- Skipping a zero in the quotient when the divisor doesn't fit.