World Population Day is observed on? 

20 + 160/? × 20 = 420

Find the simplified value of the given expression

12.5% of 384 - 16.66% of 66 = √16 + √? + 2²

What value should come in place of the question mark (?) in the following question?

60% of 120 – ?% of 64 = 20% of 200

Simplify the following expressions and choose the correct option.

45% of 640 + (2/5 of 350) = ?

5/13 × 104 + 1(2/9) × 198 = 133 + ?

1555.5 + 1000.8 – 1354.3 = ? + 52

√1225 ÷ √49 × √225 = ?² – 6 

(√7225 x √1225)/(√625) = ?

1550 ÷ 62 + 54.6 x 36 = (? x 10) + (28.5 x 40)