Option 4 : 3234

**Concept Used:- **

Multiplication of two digit numbers using nearest base of 10.

**Method and Calculation:- **

• Break the product in nearest base of 10

42 × 77 = (40 + 2) × (80 - 3)

• Open the brackets by multiplying numbers inside bracket.

42 × 77 = 3200 + 160 - 120 - 6 = 3234