Page 32 - Viva

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Number of red balls = 4 5

Number of blue balls = 7 8
Number of green balls = + 9 8

Total number of balls = 2 2 1 (actual value)

221 when rounded off to the nearest 10 gives 220.
So, the estimated number of balls is close to the actual number of balls in the
box.

Exercise 2.3

1. Add the following using the expanded form.

(a) 224, 136 and 490 (b) 379 and 583

(c) 305, 148 and 525 (d) 183 and 456

2. Estimate the following sums by rounding off the addends as mentioned.

(a) 267 + 178 + 215 (to the nearest 10)
(b) 364 + 496 + 110 (to the nearest 100)

3. Solve the following problems using estimation method.
(a) There are 235 red roses, 456 pink roses and 189 white roses in a garden.
Estimate the total number of roses in the garden by rounding off each number
to the nearest 100.

(b) There are 145 red shirts, 238 blue shirts and 295 green shirts in a cloth shop.
Calculate the total number of shirts using estimation method by rounding off
each number to the nearest 100. Check whether the estimated sum is close to

the actual sum or not.
(c) Kartik has 175 red marbles, 295 blue marbles and 164 black marbles. Estimate
the total number of marbles he has by rounding off each number to its
nearest 10.

Word Problems
Let’s look at the given examples.

Example 9: There are 362 pages in Anuj’s storybook, 224 pages in Riya’s storybook
and 113 pages in Shaina’s storybook. How many pages are there in all the
storybooks?

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