How many such pairs of letters are in the word

2916 ÷ 54 = ? + 27

The value of 5³ × 5⁴ × 5² = ?

What are the values of k, if the roots of the equation x² + 2(k - 4)x + 2k = 0 are equal?

121/? = ?/144

What value should come in place of (?) question mark in the given expression.

3³ + 4² × 5 − 52 = ?

?% of 740 – 8% of 650 = 7.2

What approximate value should come in the place of question mark in the following questions?

(49.6 × 19.8) ÷ 9.9 = ?

? = 20% of 1200 + 256

535 + ? × 27 - 22 × 20 = 230