014. Powers and Index Notation

Learning Intentions

  • To know the meaning of the terms: powers, index form, basic numeral, base number and index number
  • To understand what means when and are whole numbers
  • write a product in index form if there are repeated factors
  • Evaluate numeric expressions involving powers Use multiplication

Pre-requisite Summary

  • Understanding multiplication as repeated addition
  • Knowledge of multiplication facts
  • Understanding repeated multiplication (e.g. )
  • Ability to multiply whole numbers
  • Understanding mathematical notation and brackets

Worked Examples

Worked Example 1

Identify the terms in:

a)

b)

Worked Example 2

Write in expanded form:

a)

b)

c)

Worked Example 3

Write in index form:

a)

b)

c)

Worked Example 4

Evaluate using multiplication:

a)

b)

c)

Worked Example 5

Evaluate expressions involving powers:

a)

b)

c)

Problems

Problem 1

Identify the terms:

a)

b)

Problem 2

Write in expanded form:

a)

b)

c)

Problem 3

Write in index form:

a)

b)

c)

Problem 4

Evaluate:

a)

b)

c)

Problem 5

Evaluate expressions:

a)

b)

c)

Exercises

Understanding and Fluency

Exercise 1.

Identify base and index:

a)

b)

c)

Exercise 2.

Write in expanded form:

a)

b)

c)

Exercise 3.

Write in index form:

a)

b)

c)

Exercise 4.

Evaluate powers:

a)

b)

c)

Exercise 5.

Evaluate expressions:

a)

b)

c)

Exercise 6.

Mixed practice:

a)

b)

c)

Reasoning

Exercise 7.

Explain what means in words.

Exercise 8.

A student says . Explain the mistake.

Exercise 9.

Compare and . Which is larger? Explain.

Exercise 10.

Why is equal to ?

Problem-solving

Exercise 11.

A cube has side length . The volume is . Evaluate the volume.

Exercise 12.

A square has side length . The area is . Solve the area.

Exercise 13.

Find the value of .

Exercise 14.

A number is written as . Write this as repeated multiplication and evaluate.

Exercise 15.

Evaluate .

Potential Misunderstandings

  • Students may think means
  • Students may confuse base and index
  • Students may stop multiplying too early when expanding powers
  • Students may incorrectly write repeated multiplication in index form
  • Students may evaluate multiplication before powers incorrectly
  • Students may think instead of

Next: 015. Prime Factorisation Using Factor Trees