Question

2 - digit x 2 - digit with no reg
2.
21
x 42

Explanation:

Step1: Multiply by ones - digit

Multiply 21 by 2: $21\times2 = 42$.

Step2: Multiply by tens - digit

Multiply 21 by 40: $21\times40=840$.

Step3: Add results

Add the two products: $42 + 840=882$.

Answer:

882