Week 2: Factors, Multiples, Squares and Primes


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This week we will review the definitions of the following terms:

  • Integers: Positive and negative whole numbers (not decimals or fractions)
  • Factors: Numbers that can be divided into a larger number with no remainder.
  • Multiples: The resulting number of multiplying two smaller numbers.
  • Square numbers: When result when you multiply a number by itself (eg. 3 x 3 = 9)
  • Prime numbers: Numerals with only two factors – one and themselves.


Please write ten examples of each of the terms listed above. Use the following numbers to create a ‘factor tree”: 24; 120; 128; 130; 240; 360; 480.

We will practise our multiplication tables and learn more about prime numbers using the game “Multo”.

Prime Numbers and Factors

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Today we are going to use Erastothene’s Sieve to find the prime numbers up to 100. You will use the “Count By” app on the iPods or iPads or your netbook with the interactive 100 chart program. Color in the corresponding numbers on your paper 100 chart.

Prime numbers are numbers with exactly two factors – you can divide a prime number by one or itself, but no other number, to get a whole number. The number one only has one factor, so it is not a prime number. So, 2 and 3 are the first two prime numbers. 4 is not a prime number because it has three factors (1, 2 and 4). Circle the prime numbers on your paper chart and stick it firmly in your work book to refer to later.

Multo – a maths game for middle years


This fun game helps students to remember their times tables and understand what prime numbers are. Print out cards with each of the timestables from 0 x 0 to 9 x 9. Students draw up 4 x 4 grids and place 16 numbers from zero up to 81 in the boxes. The teacher calls out the timestable cards randomly, while students cross the answer the sum called off their grids. If they get four numbers in a line (column, row, diagonally) or four corners they call “MULTO“!

Which numbers should not be used in the grids and why? What numbers are most likely to be called and why?