Question

What is the 1st mistake...

Answer 1

Answer:

$\Large \boxed{\mathrm{Step \ 4}}$

Step-by-step explanation:

$20 +20 \div 4-2$

Division should be performed first, not subtraction.

$20+5-2$

Answer 2

Answer:

$\huge\boxed{Step \ 3}$

Step-by-step explanation:

In Step # 3, We need to divide rather than to subtract. So, the first mistake is done in step 3.