Number (mult/div)
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Grade 5

EXT: Multiply 3 numbers together


When multiplying $3$3 numbers together we are finding how many groups of how many groups there are. This is a bit of a tricky concept so let's use an example to help us think about it.

Let's imagine I have $12$12eggs in a carton, I have $8$8 cartons in a box, and I have $5$5 boxes. I want to know how many eggs I have in total. Well I can use multiplication to add up all the eggs in all the cartons in all the boxes.


The best way to find the solution is to multiply in parts. I can multiply any two numbers at a time and then add them together. First I could multiply $5\times8$5×8 to get $40$40, then I replace the "$5\times8$5×8" with "$40$40" to multiply $40\times12$40×12 and I get a total of $480$480 eggs.

Watch this video to see how this example is done.


We can multiply numbers in any order.



Question 1

FInd $2\times3\times40$2×3×40.

Question 2

Find $4\times50\times5$4×50×5.

Question 3

Calculate $3\times3\times48$3×3×48.

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