Estimate each of the following products by rounding off each number to nearest tens:

(a) 87 × 32

(b) 311 × 113

(c) 3239 × 28

(d) 1385 × 789

(a) Rounding off 87to nearest tens = 90

Rounding of 32 to nearest tens = 30

90 × 30 = 2700

(b) Rounding off 311 to nearest tens = 310

Rounding of 113 to nearest tens = 110

310 × 110 = 34100

(c) Rounding off 3239 to nearest tens = 3240

Rounding of 28 to nearest tens = 30

3240 × 30 = 97200

(d) Rounding off 1385 to nearest tens = 1390

Rounding of 789 to nearest tens = 790

1390 × 790 = 1098100