Before you practice the work from this chapter, take some time to go over some of the addition and subtraction strategies and problems we've looked at. These include:
using a number line
modelling with place value (base ten) blocks
partitioning numbers by place value
using a vertical algorithm
We also looked at how to use a vertical algorithm to solve addition or subtraction. This strategy is useful if we need to trade, or regroup. For addition, we regroup to the higher place value, but for subtraction, we regroup down to a lower place value.
Find the value of 796 - 429.
Find the value of 7681 + 9273.
Find the value of 55\,872-2619.
There are different strategies we can use to solve addition or subtraction questions. Even if our numbers get bigger, we can still use the same strategies, just with more steps.
Select and apply efficient mental and written strategies and appropriate digital technologies to solve problems involving all four operations with whole numbers and make estimates for these computations