? = 3/5 of 4/7 of 7/9 of 425
? ? = 3/5 x 4/7 x 7/9 x 425 = 113.33 = 113

137% of 12345 = ?
? ? = 12345 x 137/100 = 16912.65 ? 17000

?= 12.49% of 839.859 ? 12% of 840
= 840 x 12/100 = 100.80 ? 100

? = 5103 x 121/100
= 61.74.63 = 6000

? = 124.35% of 8096
= (8096 x 124.35)/100 = 1006737.6/100
= 10067.376 = 10000

(9.95)² x (2.01)³ = 2 x (?)²
Here, 9.95 is Approximated to 10, 2.01 is approximate to 2 because calculating the square or cubes of whole number is much easier than to calculate the square or cube of decimal numbers
2 x (?) ² = ( 10)² x (2)³ = 100 x 8 = 800
? (?)² = 400
? ? =20

99.999 ÷ 0.99 ÷ 0.00991234
= 100 ÷ 1 ÷ 0.01 = 10000

[137 ÷ 17 x 3.99]/[4.02 x 3.98] = ? ? (137 ÷ 17 x 4) / (4 x 4) ? 2

? = 95^3.7 ÷ 95^0.9989 = 95^?
? 95^{(3.7 - 0.9989)} = 95^?
? 95^2.7011 = 95^?
? ? = 2.7011 ? 2.7

3 ^7.5 ÷ 27^1.5 x 9² = 3^?
? 3^7.5 ÷ (3)^{3 x 15} x 3^{2 x 2} = 3 ^?
? 3^{7.5 - 4.5 + 4} = 3^? ? 3⁷ = 3^? ? ? = 7