Squares, roots and powers

1.2.1 Try some yourself

Activity 3

Without using your calculator, find the following:

  • (a) 102

  • (b) 1002

  • (c) 0.12

  • (d) 0.012

  • (e)

  • (f) (3)2

  • (g) (1)2

Answer

  • (a) 102 = 10 × 10 = 100

  • (b) 1002 = 100 × 100 = 10 000

  • (c) 0.12 = 0.1 × 0.1 = = 0.01

  • (d) 0.012 = 0.01 × 0.01 =

      = 0.0001

  • (e)

  • (f) (3)2 = 3 × 3 = 9

  • (g) (1)2 = 1 × 1 = 1

Activity 4

Explain why brackets should be used when writing the expression (1)2.

Answer

If you write 12 it is not clear whether you mean to square 1 first then make the answer negative, giving 1, or to square 1, giving 1. Many calculators would assume you meant (1)2, and return the answer 1.

Activity 5

Use your calculator to find the following, using your answers to the appropriate parts of Question 1 as estimates.

  • (a) 962

  • (b) 10.652

Answer

  • (a) Rough check: 1002 = 10 000.

    Calculator gives 962 = 9216.

  • (b) Rough check: 102 = 100.

    Calculator gives 10.652 = 113.4225.