A mental strategy which uses addition or subtraction to cross a number boundary.

Splitting an object or value down into smaller parts.

The point at which numbers change into 100s numbers, or from one set of hundreds to another.

Add and subtract to and from a 3-digit number bridging 100

Maths

In this unit pupils will use knowledge of place value to represent a 3-digit number in different ways. They will compare and order 3-digit numbers and position on number lines and unmarked number lines. In the future unit pupils will compare and order 4-digit numbers. They will learn what rounding is and will round 4-digit numbers to the nearest thousand, hundred and ten.

 In the prior unit pupils explored the counting sequence to 100 and beyond representing the numbers from 20-99 in different ways including on a number line They learned to represent 20-99 as a length In this unit pupils will use knowledge of place value to represent a 3-digit number in different ways They will compare and order 3-digit numbers and position on number lines and unmarked number lines

Representing 3-digit numbers, comparing and positioning on number lines

How would you partition 6 to calculate 97 + 6 efficiently?

How would you partition 7 to calculate 105 − 7? 

Which calculations cross a 100s boundary? 

Use the number line to complete the calculation. 370 + {{ }} = 420

Use the number line to complete the calculation. 550 − {{ }} = 480

How can 60 be partitioned into two parts?

The total height of Peter and the boxes is 300 cm. Peter is 80 cm tall. How high are the boxes? 

This lesson will soon be taken down.

Add and subtract to and from a 3-digit number bridging 100

Lesson outcome