Long multiplication: watch it solved step by step

Multiply digit by digit, carry, and add the partial products. Level: KS2 / KS3. Type any problem of this kind and the Lab works it out and animates every move, with a plain-words explanation of why.

Worked example: 123 × 45

1. Set out the multiplication. We multiply 123 by each digit of 45 in turn, starting from the ones digit, then add the rows up. Each new row starts one place further left (a zero holds the place).
2. 5 × 3 (ones row). 5 × 3 = 15. Write 5 and carry 1.
3. 5 × 2 (ones row). 5 × 2 + 1 = 11. Write 1 and carry 1.
4. 5 × 1 (ones row). 5 × 1 + 1 = 6. Write 6.
5. 4 × 3 (tens row). 4 × 3 = 12. Write 2 and carry 1.
6. 4 × 2 (tens row). 4 × 2 + 1 = 9. Write 9.
7. 4 × 1 (tens row). 4 × 1 = 4. Write 4.
8. Add the rows. Now add the partial products: 615 + 4920 = 5535.
9. The answer. 123 × 45 = 5535.

Answer: 5535

Practise long multiplication with problems the Lab marks for you.