Page 33 - Math 4

Fundamental Operations Fundamental Operations

2. Let's apply the above tricks mentally. Then, tell and write the answer
as quickly as possible. It is your mental maths!

a) 1 + 9 + 7 = b) 8 + 6 + 2 = c) 9 + 3 + 7 =

d) 15 + 4 + 5 = e) 14 + 6 + 7 = f) 3 + 12 + 8 =

g) 14 + 2 = h) 25 + 3 = i) 32 + 34 =

j) 25 – 13 = k) 36 – 14 = l) 44 – 21 =

m) 53 – 22 = n) 67 – 35 = o) 78 – 55 =

3. Let's write the missing numbers and then add as quickly as possible.

a) 2 + 7 + 8 = + 7 = b) 6 + 14 + 9 = + 9 =

c) 5 + 3 + 27 = 5 + = d) 45 + 8 + 5 = 8 + =

e) 4 + 17 + 6 + 3 = 10 + =

f) 7 + 25 + 13 + 5 = 20 + =

g) 12 + 14 = (10 + 10) + + 4) =

h) 23 + 25 = (20 + ) + (3 + 5) =

i) 15 + 12 = ( + ) + (5 + 2) =

j) 33 + 32 = (30 + 30) + ( + ) =
4. Let's write the missing numbers and then subtract as quickly as
possible.

a) 27 – 14 = (27 – 10) – =

b) 36 – 13 = (36 – ) – 3 =

c) 45 – 21 = (45 – ) – 1 =

d) 28 – 12 = (20 – 10) + (8 – ) =

e) 27 – 15 = (20 – ) + (7 – 5) =

f) 39 – 26 = (30 – 20) + ( – ) =
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Approved by Curriculum Development Centre, Sanothimi, Bhaktapur vedanta Excel in Mathematics - Book 4