Explain that to subtract to 100,000 with simple numbers, you can split the second number into ten-thousands numbers and thousands numbers. Then you subtract them from the first number in parts. In the given problem, you do this by first subtracting 20,000 and then 8,000. Show that you can also use the number line to subtract the second number in parts. The students solve the next three problems on their own. Discuss which method they have used to solve the problems. For the story problem, first have the students take the problem out of the story. Then you have them split the second number into hundreds numbers and tens numbers. Then you have them subtract the second number in the first in steps. The students will solve the next two story problems on their own. Discuss which methods the students have used to solve these problems.
Check whether the students can subtract to 100,000 with simple numbers with the following question:
- Which method do you use to subtract to 100,000 with simple numbers?