Bridging is a strategy which uses addition or subtraction to cross a number boundary.

Partition means splitting an object or value down into smaller parts.

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

Solve problems by adding and subtracting to or from 3-digit numbers

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 should you partition 60 to calculate 160 + 60? 

How should you partition 60 to calculate 210 − 60? 

Colin the cat is 410 cm high in a tree. He climbs down 50 cm. How high is he now? 

Katya is in a tree. She climbs down 30 cm. She is now 288 cm high. How high was she when she started? {{ }} cm

How should you partition 5 to calculate 98 + 5? 

Which calculations cross a 100s boundary? 

Which calculation is shown by the number line representation?

Use the number line to find the missing number. 510 − ___ = 460

This lesson will soon be taken down.

Solve problems by adding and subtracting to or from 3-digit numbers

Lesson outcome