Multiplying and dividing by 8 | Year 4 Mathematics PDF Download

Counting in 8s

• Count forwards and backwards in increments of eight using a counting stick.
  
• If we know the answer to a multiplication problem, we can use it to solve related unknown problems by adding or subtracting.

Multiplication Fact:

• Utilize the counting stick to determine 6 x 8.
• 6 x 8 = 48
• If we know 6 x 8, we can find 7 x 8 by adding another 8.
• 7 x 8 = 56

Example

Example: There are 11 octopuses swimming near the shore. How many legs are there altogether?

Sol: We know that octopuses have 8 legs, so the equation we need to work out is 11 x 8.
We know from looking at the number stick that:
10 x 8 = 80
So to find 11 x 8 we add another 8.
11 x 8 = 88
So, there are 88 legs altogether.

Dividing by 8

• Division facts are essentially number sentences linked to a specific times table, in this case, the 8 times table.
• If we know, for instance, that 6 multiplied by 8 equals 48, a related division fact would be 48 divided by 8 equals 6.
• We can utilize known division facts to figure out unknown division facts effectively.

Example

Example: Sharing Sweets Equally
Imagine we have 56 sweets and we plan to distribute them among 8 individuals.

• Through the division operation, 56 divided by 8 equals 7.
• Given that 56 divided by 8 is 7, we can deduce that 56 divided by 7 equals 8.