Åk 6–9
 
English/فارسی
2.7 Exercises – Addition and subtraction

1. Do the calculations according to the example below.

Ex: 11 + 22 (10+20) + (1+2) = 33
a) 24 + 51
b) 76 - 24
c) 32 + 47
d) 94 - 61
e) 574 + 203
f) 2,371 + 3,428
g) 9,687 - 4,585
 

2. First make tens and calculate like the example below.

Ex: 8 + 9 + 5 = 20 + 2 = 22
a) 4 + 7 + 6 + 2 =
b) 3 + 4 + 1 + 7 =
c) 25 + 4 + 5 + 6 =
d) 18 + 5 + 32 + 2 =
e) 42 + 5 + 28 + 23 =
f) 9 + 3 + 34 + 46 =
g) 24 + 36 + 12 + 3 =
 
3. Do the calculations by using approximation. 
Ex: 46 + 32 ≈ 50 + 30 = 80
a) 23 + 19 ≈
b) 67 - 34 ≈
c) 54 - 22 ≈
d) 69 + 28 ≈
e) 53 + 66
f) 72 + 56 ≈
g) 93 - 27 ≈
 

4. Round off first to the hundreds and then calculate by using approximation.

Ex: 290 + 118 ≈ 300 + 100 = 400
a) 753 + 275 ≈
b) 486 - 91 ≈
c) 867 + 151 ≈
d) 174 + 748 ≈
e) 425 - 127 ≈
f) 819 - 311 ≈
g) 367 + 474 ≈