How many such pairs of letter are there in the word

What will come in the place of question mark (?) in the given expression?

25% of 1280 + (41 × 4) = ?² 

672 ÷ 28 × 24 + 363 – 309 =?

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

65% of 460 − (3/4 of 160) = ?

4567.89 - 567.89 - 678.89 = ?

9999² + 1111² =?

[3/5 of (31 + 44) – 10] ÷ 7 = ?

729^2/3 = ?

116*2/3% of 18600 + 666*2/3% of 1290 = 457*1/7% of 1750 + 555*5/9% of 3150 + ?

15% of 695 – 12.5% of 250 =? – 1200

Simplify the following expressions and choose the correct option.

{[(96 ÷ 3) × (5/8)] + 7²} ÷ 9 = ?