# Maths KS1 / KS2: How to use arrays to multiply

**Mr Sharma needs to buy new pencils for the school but they only come in boxes of 5.**

How does he know how many he’s got? His attempts at guessing leave Mrs Barker in a sticky situation.

This sounds like a job for Multiplication Boy! Luckily, our hero in a world without maths knows what to do.

He speeds up Mr Sharma’s counting by showing him how to use arrays to multiply.

Multiplication Boy and Mr Sharma also explore the commutative law of multiplication to solve some counting confusion.

Will Mr Sharma be able to work out exactly how many pencils he’s buying? Will Mrs Barker manage to escape her pencil prison? And will the children ever actually get their new pencils?

*Teacher Notes*

*Children could continue the learning with multiplication problems based on the story.*

*For example: Mr Sharma has got all the pencils he needs, but he also wants some paper. He has 3 packets of paper, and in each packet there are 10 pieces of paper. How many pieces of paper is that in total? What is the calculation?*

*How can you show this as an array? Children could use counters, pegs or images to create arrays to help them to solve similar multiplication problems.*

*Some children might begin to explore the commutative law of multiplication by writing out the related multiplication calculations once they have created or drawn an array (e.g. 3 x 10 = 30 so 10 x 3 = 30).*

*Curriculum Notes*

*This clip will be relevant for teaching Maths at KS1 and KS2 in England and Wales, and First and Second Level in Scotland.*