A strategy that involves using a  multiple of ten as a 'bridge', so numbers can be partitioned to make use of bonds to ten.

Use bridging to solve addition and subtraction problems

Maths

In this unit pupils will add and subtract 1s and 10s from 2 digit numbers. They will use number facts to add/subtract a single-digit number to/from a 2-digit number. They will use a part-part-whole model to represent addition and subtraction. In the future unit pupils will learn to find 10 more or less than a 2-digit number They will  add and subtract 10 to/from a 2-digit number using number facts

In the prior unit pupils added 3 addends. They used strategies such as finding 2 addends to total 10 or 2 numbers to bridge though 10. In this unit pupils will add and subtract 1s and 10s from 2 digit numbers. They will use number facts to add/subtract a single-digit number to/from a 2-digit number. They will use a part-part-whole model to represent addition and subtraction.

Adding and subtracting ones and tens to and from 2-digit numbers

Which equation would be used to solve this problem? There were 42 children. 7 were sitting down and the rest were standing up. How many were standing up? 

Alex had put 47 cubes into the tray and then he found 6 more. How many cubes are there altogether? {{ }} cubes.

Sam collected 54 pencils. He kept some to use and put some away in a pot. He put 46 in the pot. How many does he now have to use? {{ }} pencils. 

Which of these equations can be solved by bridging a multiple of 10? 

Which of these known facts could help you in solving this equation? 46 + 8 = ___

Look at the ten frames. Which equation does the image represent by showing ‘bridging 10’ to subtract? 

Look at the number line. How should 8 be partitioned to ‘bridge 10’ when subtracting?  

How could we solve this equation? 23 − 6 = ?  

Which number is missing from this number line?

Look at the number line. What is the missing multiple of ten?  

This lesson will soon be taken down.

Use bridging to solve addition and subtraction problems

Lesson outcome