Let's try a practice problem to remember how patterns can help us with addition and subtraction.
Fill in the boxes with the missing numbers.
14+5=⬚
24+5=⬚
34+5=⬚
84+5=⬚
What is the pattern? Choose the correct answer:
We can use number lines and patterns to add numbers together.
12-4=8. Use this to find:
22-4=⬚.
32-4=⬚.
42-4=⬚.
72-4=⬚.
To add or subtract using patterns, compare the calculation that you are trying to work out to another calculation that you already know. If you can see a pattern between the numbers, then you can use that to find the answer.
Sometimes our problem is in the form of a story, or sentences. In this video, we see how to work out our number problem from the key words, or clues.
Four friends are picking fruit in an orchard. Tricia picks 16 apples, Ryan picks 29 peaches, James picks 23 pears and Laura picks 15 plums.
How many pieces of fruit were picked in total?
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.
addition | 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
selects and applies appropriate strategies for multiplication and division, and applies the order of operations to calculations involving more than one operation
analyses and creates geometric and number patterns, constructs and completes number sentences, and locates points on the Cartesian plane