Page 12 - 新思维数学活动用书5 样章

1.2 Rounding decimal numbers

1.2 Rounding decimal numbers

Worked example 2

A number with 1 decimal place is rounded to the nearest

nearest whole number. round

a What is the smallest number that rounds to 10? round to the nearest...
b What is the largest number that rounds to 20?

You can use a number line

to help you.

9 10 11 19 20 21

a 9.5 If the tenths digit is 5, 6, 7, 8 or 9 the number rounds
up to the nearest whole number.

b 20.4 If the tenths digit is 0, 1, 2, 3 or 4 the number rounds
down to the nearest whole number.

Exercise 1.2

Focus

1 Here is part of a number line. The arrow shows the position of a number.

33 34 35

Complete the sentence for this number.

rounded to the nearest whole number is .

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