To work out an answer, often by adding or subtracting.

Not wasting time or effort. An efficient strategy is one we can carry out easily.

Use efficient addition strategies to calculate

Maths

In this 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 future unit pupils will add 3 addends, understanding they can be added in any order, bridging through 10.

In the prior unit pupils added and subtracted 1s and 10s from 2 digit numbers. They used number facts to add/subtract a single-digit number to/from a 2-digit number and used a part-part-whole model to represent addition and subtraction. In this 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.

Addition and subtraction of two 2-digit numbers

Izzy wants to solve the equation 2 + 4 + 50 = ? Which is the most efficient strategy to use?

Andeep estimates the cost of the items shown. Which of the following is most likely to be accurate?

For which of the following equation, would you use the bridge 10 strategy?

For which equations would you use the known facts strategy? Tick two.

Andeep’s items cost £35     Which of the following shows the cost of Izzy’s items?

Match to show which equations will have the same sum.

Look at the items in the shop. How much would a ball and a car cost? £{{ }}

Izzy buys an astronaut and a rocket. Which known fact would she use to help her calculate the cost?

Andeep spent £43 at the shop. Which two items did he buy?

Which known fact would you use to calculate the cost of a penguin and an astronaut?

Which known fact would you use to calculate the cost of a unicorn and a car?

Andeep uses the 'bridge 10' strategy to find the cost of two items. Which two items were they?

This lesson will soon be taken down.

Use efficient addition strategies to calculate

Lesson outcome