Page 163 - New Medley 4 Semester 1

Estimating Product

Example 12: Estimate 489 × 263 by rounding to nearest tens.

Solution: Rounding off to nearest tens

489 is rounded off to 490

263 is rounded off to 260

Estimate of product: 490 × 260 = 127400.

Example 13: Estimate 1287 × 2012 by rounding to nearest hundreds.

Solution: Rounding off to nearest hundreds

1287 is rounded off to 1300

2012 is rounded off to 2000

Estimate of product: 1300 × 2000 = 2600000.

EXERCISE 3.9

A. Estimate the product by rounding to nearest tens.

1. 315 × 398

2. 158 × 532

3. Each packet has 124 combs. Estimate the number of combs contained
in 323 such packets by rounding to nearest tens.

B. Estimate the product by rounding to nearest hundreds.

1. 314 × 412

2. 503 × 287

3. Each packet has 321 pens. Estimate the number of pens contained in
512 such packets by rounding to nearest hundreds.

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