This document provides examples and steps for performing addition, subtraction, and multiplication through mental math and process math. It includes modeling addition and subtraction with carrying and regrouping, as well as examples for students to practice. The key strategies emphasized are adding and subtracting by tens and ones, counting differences by tens then ones, and trying mental math before using algorithms.

1. Process Math and Mental MathProcess Math and Mental Math

2. Model:
50 + 30 =
Steps:
1.think 30
2.add 5 tens…(5 fingers)
say 40, 50, 60, 70, 80
3.the answer is 80
Practice:
60 + 10 = _____
30 + 20 = _____
20 + 40 = _____
50 + 40 = _____
80
70
50
60
90

3. Model:
53 + 35 =
Steps:
1.think 35
2.add 3 ones…(hold up 3 fingers) 36,
37, 38
3.add the 5 tens…(hold up 5 fingers)
48, 58, 68, 78, 88
4.the answer is 88
Practice:
62 + 11 = _____
35 + 23 = _____
27 + 42 = _____
56 + 41 = _____
88
73
58
69
97

4. 4 3 6 1 7 5
+ 2 1 + 1 7 + 2 2
4 1 6 0 3 4
+ 1 8 + 2 7 + 2 2
Model:
5 3
+ 3 3
Steps:
1.3 + 3 write answer for ones
2.3 + 5 write answer for tens
3.the answer is 86
68 46 87 79
95 78 65

5. Model:
60 - 30 =
Steps:
1.think 30
2.count difference by tens …
say 40, 50, 60 (3 fingers = 30)
3.the answer is 30
Practice:
60 - 10 = _____
70 - 40 = _____
50 - 30 = _____
90 - 50 = _____
30
50
30
20
40

6. Model:
53 - 32 =
Steps:
1.Think 32
2.count difference of ones...
think 32, count to 33 (1 finger = 1)
3.count difference of tens… think
33 count to 53 (2 fingers = 20)
4.the answer is 21
Practice:
62 + 11 = _____
35 + 23 = _____
27 + 42 = _____
56 + 41 = _____
21
73
58
69
97

7. 4 3 7 7 7 5
- 2 3 - 1 2 - 2 4
4 8 6 7 7 7
- 2 1 - 3 0 - 2 4
Model:
5 3
- 3 3
Steps:
1.count difference of ones
count from 3 to 3 = 0
write 0 under ones
2.count difference of tens,
count from 3 to 5 = 2
write 2 under tens
3.the answer is 20
02
02 55 15
74 73 35

8. ∗ Ones before Tens
∗ Add by tens (if zeros are in the ones places)
∗ Add by ones then tens
∗ Count difference by tens (if zeros are in the ones places)
∗ Count difference by ones then tens
∗ Try mental math first
∗ Use algorythm last