Page 19 - 新思维数学学生用书9 样章

1 Number and calculation

Check your progress

1 Write whether each number is rational or irrational.
a 4 b 5 c 625
.
d 62 5 e 625
.
2 Write whether each number is rational or irrational. Give a reason for each answer.
a 3 + 4 2 b 9 + 7
2
3 Without using a calculator, find an integer n such that n < 50 < n +1.
3
4 Write each number in standard form.
a 86 000 000 000 b 0.000 006 45

5 Write these numbers in order of size, smallest first.
A = 9 × 10 B = 6 × 10 C = 8 × 10 D = 7.5 × 10 −4
−5
−4
−3
6 Write each number as a fraction.
a 7 −2 b 3 −4 c 2 −7
7 Write each number as a power of 5.

a 125 b 1 c 0.04
8 Write the answer to each calculation as the power of a single number.
a 6 × 6 − 3 b 12 × 12 − 3
−
2
8
c 4 ÷ 4 8 d 15 ÷ 15 − 6
−
2
4

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