question_answer

Estimate the following products:

(a) \[87\times 313\]

(b) \[9\times 795\]

(c) \[898\times 785\]

(d) \[958\times 387\]

Make five more such problems and solve them

Answer:

(a) \[87\times 313\]

\[\because \]       87 \[\to \] 90

[Rounding off to nearest tens]

313 \[\to \] 300

[Rounding off to nearest hundred]

\[\therefore \] Estimated product \[=90\times 300=27,000\]

(b) \[9\times 795\]

\[\because \]       9 \[\to \]10

[Rounding off to nearest tens]

795 \[\to \] 800

[Rounding off to nearest hundred]

\[\therefore \] Estimated product \[=10\times 800=8,000\]

(c)        \[898\times 785\]

\[\because \]       898 \[\to \] 900

[Rounding off to nearest tens]

785 \[\to \] 800

[Rounding off to nearest hundred]

\[\therefore \] Estimated product \[=900\times 800=7,20,000\]

(d) \[958\times 387\]

\[\because \]       958 \[\to \] 1000

[Rounding off to nearest thousand]

387 \[\to \] 400

[Rounding off to nearest hundred]

\[\therefore \] Estimated product \[=1000\times 400=4,00,000\]