Easy Subtraction Problems

This will be problems such as 60 - 20, 36 – 6, 49 – 7, 34 – 20.

e. g. 60 – 20
To solve a problem like 60 – 20, take the tens digits as ones and subtract them.
60 ones = 6 tens
20 ones = 2 tens
6 tens - 2 tens = 4 tens
4 tens = 40
So, 60 - 20 = 40

Solve these problems using the above method.
Practice 1:
40 - 30
40 ones = 4 tens
30 ones = (3) tens
4 tens - (3) tens = (1) ten
(1) ten = (10) ones

Practice 2:
50 - 40
(5) tens - (4) tens = (1) tens
(1) ten = (10) ones

e. g. 36 – 6
To solve a problem like 36 – 6, use the system of numeration.
36 = 3 tens + 6 ones
6 = 6 ones
3 tens & 6 ones - 6 ones = 3 tens or 30 ones
So, 36 - 6 = 30

Solve these problems using the above method.
Practice 1:
48 – 8
48 = 4 tens + 8 ones
8 = (8) ones
4 tens & (8) ones – (8) ones = (4) tens
(4) tens = (40) ones

Practice 2:
23 -3
23 = (2) tens + (3) ones
3 = (3) ones
(2) tens & (3) ones – (3) ones = (2) tens
(2) tens = (20) ones

Solve Mentally:
1. 55 – 5
2. 67 -7
3. 48 – 8
4. 92 – 2

e. g. 49 – 7
To solve a problem like 49 – 7, split the 49 into ones and tens and subtract the ones. Then use system of numeration to add tens and ones.
49 = 40 + 9
9 – 7 = 2
40 + 2 = 42
So, 49 – 7 = 42

Solve these problems using the above method.
Practice 1:
48 – 6
48 = 40 + 8
8 – (6) = (2)
40 + (2) = (42)

Practice 2:
28 - 3
28 = (20) + (8)
(8) – (3) = (5)
(20) + (5) = (25)

Solve Mentally:
1. 54 – 3
2. 86 – 2
3. 48 – 4
4. 66 – 5
5. 87 – 6
6. 35 – 3

e. g. 34 – 20
To solve a problem like 34 – 20, split the 34 into ones and tens and subtract the tens. Then use system of numeration to add tens and ones.
34 = 30 + 4
30 – 20 = 10
10 + 4 = 14
So, 34 – 20 = 14

Solve these problems using the above method.
Practice 1:
54 – 30
54 = 50 + (4)
50 – (30) = (20)
(20) + (4) = (24)

Practice 2:
68 – 20
68 = (60) = (8)
(60) – (20) = (40)
(40) + (8) = (48)

Solve Mentally:
1. 77 – 30
2. 48 – 20
3. 56 – 10
4. 65 – 40
5. 89 – 60
6. 38 – 20