Route through subtraction
4th
Children now learn how to manage exchanges where adjustments are needed from one value to another.
e.g.
563 - 248 =
500 +
60 + 3
- 200
+ 40 + 8
300 + 10 + 5
315
50
13
Children then extend this to numbers which involve more than one exchange and exchanges at different points within the numbers.