Explain how doubling and halving are related

Maths

Double 2-digit numbers and record as multiplications where one of the factors is 2

Halve even 2-digit numbers and multiples of 10

Identify missing factors when one factor is 2

Use knowledge of doubling, halving and the 2 times table to solve problems

In this unit pupils will learn how multiplication with 2 as a factor relates to doubling and how we can see halving as the inverse of doubling, deriving the related halving fact from a known double. In the future unit pupils will double and halve 2 digit numbers. Pupils will use knowledge of doubling and halving and the 2x table to solve problems.

In the prior unit pupils represented the 2x 10x table in different ways. They explained the relationship between adjacent multiples of 2/10 and how factor pairs can be written in any order. In this unit pupils will learn how multiplication with 2 as a factor relates to doubling and how we can see halving as the inverse of doubling, deriving the related halving fact from a known double. 

In this unit pupils will learn how multiplication with 2 as a factor relates to doubling and how we can see halving as the inverse of doubling, deriving the related halving fact from a known double.

Multiplying by 2, doubling and halving (factors and products)

Use the bar model to complete the sentence. Half of 8 is equal to {{ }}

If I know that half of 6 is equal to 3, then I know that _____________

Which facts are represented by this bar model?

Which equation is represented by this bar model?

Alex had 4 marbles. He gave half to Jacob. How many marbles did Jacob get? {{ }} marbles

Aisha gave half of her biscuits to Alex. Aisha was left with 6 biscuits. How many biscuits did Aisha have to begin with? {{ }} biscuits

Which of these equations could I use doubling knowledge to solve?

Starter Quiz

Which double is being shown here?