question_answer

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

(a) \[87\times 32\]

(b) \[311\times 113\]

(c) \[3239\times 28\]

(d) \[1385\times 789\]

Answer:

(a) We have, \[87\times 32\]

Rounded off 87 to nearest tens = 90

and rounded off 32 to nearest tens = 30

So, estimated product\[=90\times 30=2700\].

(b) We have, \[311\times 113\]

Rounded of 311 to nearest tens = 310

and rounded off 113 of nearest tens =110

So, estimated product \[=310\times 110=34100\].

(c) We have, \[3239\times 28\]

Rounded off 3239 to nearest tens = 3240

and rounded off 28 to nearest tens = 30

So, estimated product \[=3240\times 30=97200\],

(d) We have, \[1385\times 789\]

Rounded off 1385 to nearest tens = 1390

and rounded off 789 to nearest tens = 790.

So, estimated product \[=1390\times 790\]

\[=1,098,100\]