Lesson

Do you remember some of the methods, or strategies, we've used to add numbers together?

765 + 104 = 869. Use this to fill in the gaps in the number sentences.

a

665+ ⬚ = 869

Worked Solution

b

565+ ⬚ = 869

Worked Solution

Idea summary

We can use patterns to add two numbers. If we are given one number sentence, and need to complete another, then we can compare the number sentences to find a pattern to help.

What happens when we have more than two numbers to add together? Let's see how we might approach a problem like this, in the following video.

Find the value of 540 + 44 +5.

Worked Solution

Idea summary

We can use a place value table when adding more than two numbers. We add the numbers in each column starting from the units place value.

If we have a written problem, it helps to know which words relate to addition. Looking for clues helps us find out what we need to add, as we can see in this video.

In a family, the grandmother is 73 years old, the mother is 32 years old, and the daughter is 4 years old. What is the combined age of the family?

Worked Solution

Idea summary

There are some words we might come across that mean we will be using addition whereas other words may suggest subtraction. This is not a complete list, so we need to understand the context of the question, to work out whether to add or subtract.

These words suggest addition | These words suggest subtraction |
---|---|

more | less |

longer | shorter |

later | earlier |

bought | sold |

joined | left |

selects and applies appropriate strategies for addition and subtraction with counting numbers of any size

analyses and creates geometric and number patterns, constructs and completes number sentences, and locates points on the Cartesian plane