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REAL NUMBERS โ€ข FOUNDATION PACK 1

Worked Answers

Use these answers after attempting the worksheet independently.

A. Types of Numbers

  1. a) Natural number   b) Integer   c) Rational   d) Irrational   e) Integer   f) Rational.
  2. โˆ’2, 0, 7 and โˆš16 (=4).
  3. โˆš2 and ฯ€.

B. Place Value and Ordering

  1. Six million, eighty-four thousand, two hundred and nine.
  2. 700 000.
  3. โˆ’8, โˆ’5, โˆ’1, 0, 3, 6.
  4. a) โˆ’4 > โˆ’9   b) 0.6 = 3/5   c) โˆš25 < 6.

C. Factors, Multiples and Prime Numbers

  1. 1, 2, 3, 4, 6, 8, 12, 24.
  2. 7, 14, 21, 28, 35.
  3. 13 prime; 21 composite; 29 prime; 51 composite.
  4. 84 = 2ยฒ ร— 3 ร— 7.
  5. 18 = 2 ร— 3ยฒ and 30 = 2 ร— 3 ร— 5, so HCF = 2 ร— 3 = 6.
  6. 12 = 2ยฒ ร— 3 and 15 = 3 ร— 5, so LCM = 2ยฒ ร— 3 ร— 5 = 60.

D. Directed Numbers

  1. a) 5   b) โˆ’8   c) โˆ’10   d) โˆ’24   e) โˆ’7   f) 35.
  2. 4 โˆ’ 11 = โˆ’7ยฐC.
  3. 3 โˆ’ 7 + 2 = โˆ’2, so it stops on floor โˆ’2.

E. Approximation

  1. a) 8 750   b) 8 700   c) 9 000.
  2. a) 12.7   b) 12.68.
  3. 0.0078.
  4. 49.8 โ‰ˆ 50, 20.3 โ‰ˆ 20 and 9.9 โ‰ˆ 10. Estimate = (50 ร— 20) รท 10 = 100.