Convert `(254)_8` into decimal system?

(2² × 5² ) + 4 × 6 = ? - √324

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

 (25% of 320) + (3/8 of 400) − 30 = ?

(5832)^1/3  × 10.11 × 11.97 ÷ 16.32 = ? + 45.022

82% of 400 + √(?) = 130% of 600 - 85% of 400

If (x + 1/x) = 5, then value of x³ + 1/x³ is:

Simplify: (1 ÷ 0.08)

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

{ (144 ÷ 12) × 5 } − (18 ÷ 3) = ?

Simplify the following expressions and choose the correct option.

(3/4 of 256) + (2/5 of 150) - (7² ÷ 7)

464 + 181 +? = (154 × 25) - (15) ²  

15% of 1800 + 2² = ?