2. 59 87 68 76 95 74
80 + 7 60 + 8 70 + 6 90 + 5 70 + 450 + 9

3. Dick gathered 56 shells
at the beach. He gave
24 shells to his friend.
How many shells were
left?

4. Subtract mentally the ones, then the tens
Think: 5 6 5 6
- 2 4 2 4
2 3 2
So, 32 shells were left to
Dick.

5. Example:
8 4 8 4 8 4
-2 1 2 1 2 1 63
3 6 3
7 8 7 8 7 8
-3 5 - 3 5 - 3 5 43
3 4 3

6. Digit Movement
0 - Say ‘’Yo’’
1 - Clap once
2 - Clap twice
3 - Clap thrice
4 - Raise your left hand
5 - Raise your right hand
6 - Say ‘’Ole’’
7 - Do the yes clap
8 - Say ‘’Mabuhay!’’
9 - Say ‘’ Be Happy!’’

7. Work by Pairs
Direction: Find the missing number in the
difference. Use the number coding.
1. 2. 3.
4. 5.
46
-21
2
88
-25
3
96
-24
7
78
-35
3
98
-35
6

8. 6. 7. 8.
9. 10.
95
- 25
2
29
-19
1
59
-20
3
39
-11
2
62
-51
1

9. Remember:
 To subtract 2-digit numbers
mentally without regrouping
, subtract the ones first, then the
tens. Then give the difference.

10. Subtract mentally.
1) 35 2) 56 3) 94
- 12 - 32 -72
4) 48 5) 68
-25 -34

11. Exercise:
Subtract the following mentally:
1) 74 2) 86 3) 97
-12 -35 -84
4) 94 5) 79
-72 - 51

12. Assignment:
A. Subtract mentally. Write only the answer.
1) 36 2) 89 3) 56
-12 - 36 - 34
4) 67 5) 83
-45 -51

13. 86
34
22 57
43
B. Subtract each number from 86
using mental arithmetic and
write you answers in the
triangles.