Show the problem 6,410 - 43. Explain that you can solve subtraction problems with a tens number regrouping in different ways. The girl splits the number up so that she first rounds down to a round number, before she regroups. The boy splits the number into tens numbers and ones values and subtracts this from 6,410 in steps. Discuss with the students which methods they should use to solve a problem. Then have the students solve the next three problems on their own. Afterwards, discuss the different methods of solving the problems. Show the problem 6,100 - 452. This involves regrouping of a hundreds number. Discuss the steps that the girl and the boy use to solve this problem. Then discuss with the students which other methods they could use. Next, have the students solve the next three problems on their own and then discuss the different methods of solving the problems again. For the story problem, explain that you first take the problem out of the story. Then you solve the problem in steps. In the boxes there are smaller steps, in which you first round a number and then regroup the remaining number. Have the students solve the next two story problems on their own and discuss the different methods of solving the problem once again.
Check whether the students can subtract to 10,000 with regrouping by asking the following question:
- Which method do you use to subtract to 10,000 with regrouping in steps?