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