Subtraction to 10,000 with regrouping
Lesson
Grade 4
General
Students learn to subtract to 10,000 with regrouping.
Standards
CCSS.Math.Content.4.NBT.B.4
Learning objective
Students will be able to subtract to 10,000 with regrouping of the thousands-, hundreds-, or tens number.
Introduction
Have the students solve the problems in different contexts without regrouping.
Instruction
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?
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?
Quiz
The students are given ten problems in which they practice subtracting to 10,000 with regrouping using a visual aid, in the abstract, and in story form.
Closing
Discuss with the students the importance of subtracting to 10,000 with regrouping. As a closing activity the children can form pairs and calculate how many people did not see the meerkat. Then they can also calculate how many visitors did not see the elephants.
Teaching tips
Students that have difficulty with subtracting to 10,000 with regrouping can first practice subtracting to 1,000 with regrouping and subtracting to 10,000 without regrouping with simple numbers. For this, have the students structure the numbers by arranging them under one another. Have students that have difficulty with regrouping the number that must be subtracted can split the number so that they first get a rounded number. For 9,140 - 60, for example, the students can first take away 40 and then regroup with the 20 that still has to be subtracted.
Instruction materials
MAB blocks