Teacher Guide
Week 8
Subtracting Within 100 (No Regrouping) — Teacher Guide
Monday: Subtracting Tens (Mental Math)
1
Subtract 10
1.
43, 65, 77, 32
2
Multiples of 10
1.
34, 56, 78, 63
3
Number Line
1.
45, 47
4
Number Talk
1.
75-20 is bigger (subtract less)
2.
86-10 is bigger (subtract less)
5
Challenge
1.
45, 23
Page break
Tuesday: Subtracting 2-Digit Numbers
1
Subtract Ones Then Tens
1.
23, 34, 42, 72
2
Estimation
1.
About 30, actual 35 / About 50, actual 51 / About 60, actual 63
3
Step-by-Step
1.
24, 43
4
Strategies
1.
35, 51, 72, 45
5
Word Problems
1.
23 cars, 45 balls
Page break
Wednesday: Column Subtraction
1
Column Subtraction
1.
23, 34, 42, 72
2
More Practice
1.
35, 51, 72, 45
3
Three Numbers
1.
43, 35
4
Find Error
1.
23 is correct ✓, 43 is wrong ✗ (should be 42)
5
Create Own
1.
Various: 50-16, 60-26, 70-36, etc.
Page break
Thursday: Word Problems
1
Word Problems
1.
34 shells, 56 books, 63 birds
2
Compare
1.
A=34, B=64, B is bigger
3
Two-Step
1.
34, 24, 24 stickers
4
Create Own
1.
Accept student-created problems
Page break
Friday: Review & Self-Check
1
Mental Math
1.
20, 40, 10, 70, 30, 60
2
Column Review
1.
34, 62, 54, 26
3
Mixed
1.
47, 74, 34, 63
4
Word Problems
1.
24 students, 43 pages
5
Self-Check
1.
Accept student self-assessment and reflection