Year 2 have been working out some challenging subtraction number sentences in Numeracy today. They involved subtracting a two-digit tens number from a three-digit tens number, crossing the hundreds barrier! We teach children to use mental methods when appropriate but when faced with a calculation that they cannot do in their heads, they are encouraged to use an efficient written method. How would you work out 220 – 70? What strategies would you use to help you?
Using a numberline is one example of a written method that we teach. Drawing their own numberlines to help them to work out 220 – 70, the children in the photo above all chose to use addition strategies to count up from 70 to 220. Look carefully at each whiteboard, each child’s addition steps are slightly different but, as they demonstrated when they explained their recordings to each other, each one added up to the right answer. The children were all very proud of their efforts today, as they worked hard to develop confidence and accuracy with using this numberline method.