100 + 50 * 2 = ?

Answer: Option C

Answer: Option D

Explanation:

b-[b-(a+b)-{b-(b-a+b)}+2a]
=b-[b-a-b-{b-(2b-a)}+2a]
=b-[-a-{b-2b+a}+2a]
=b-[-a-{-b+a}+2a]
=b-[-a+b-a+2a]
=b-[-2a+b+2a]
=b-b
=0

Answer: Option A

Explanation:

By taking LCM we get
=\begin{aligned} \frac{28+14+7+4+2+1}{28}
= \frac{56}{28} = 2\end{aligned}

Answer: Option C

Explanation:

Remember the formula, if not then cram it :)
\begin{aligned} 2ab = (a^2 + b^2)- (a-b)^2 \end{aligned}
=> 2ab = 29 - 9 = 20
=> ab = 10

Answer: Option B

Explanation:

\begin{aligned}
= 16-[5-(6+2(7-8+5))]
\end{aligned}
(Please check due to overline, sign has been changed)
\begin{aligned}
= 16-[5-(6+2 \times 4))]
\end{aligned}
\begin{aligned}
= 16-[-9] = 16 + 9 = 25
\end{aligned}