This term in prep, we have been investigating addition strategies and how we can add numbers efficiently.
We began by looking at counting strategies. We learned that it is easier to use the counting-on strategy rather than counting-all strategy when adding two numbers (when adding 7 and 6 together, we already know there is 7, so we don’t need to count those again. We can go 7, then 8,9…). We found that when we are counting-on, it is easier to count-on from a large number (when adding 7 and 33 more, it is easier to count-on from 33).
We ten looked at the friends of ten. We found out that all single digit numbers have another number that will make ten (0 and 10, 1 and 9, 2 and 8 etc). Knowing these facts will support them further when mentally calculating numbers.
During week 8, 9 and 10, we are investigating doubles and near-doubles. Knowing doubles is another way we can add efficiently and will help later in multiplication. By knowing our double facts, we can begin using this to work out addition of near-doubles such as 7 and 8 – 7 and 7 is 14, so 7and 8 must be one more than that…)
Not all students are ready to use these strategies and it will take practise before the children will know which strategies are suitable for each situation. We will continue to scaffold students in using these strategies when investigating problem where they need to calculate numbers.