Maths

Today, we are going to look at multiplying more than 2 numbers together - for example 3 x 8 x 4 rather than our standard times table facts. We must think carefully about which order we choose to do this multiplication in. We know that in whatever order, we will obtain the same answer because we all know that multiplication is commutative HOWEVER we want to find the most efficient methods so that you can solve these calculations mentally instead of using a written calculation.

 

What do I mean by this?

 

Well, take my example above for instance: 3 x 8 x 4. We could solve it in the order it is written in 3 x 8 = 24 and then 24 x 4 is...? I don't know the answer here...so I would have to do a written calculation.

 

BUT...what about if I jiggled the numbers around to make it 3 x 4 x 8. Then, I would calculate 3 x 4 = 12 and 12 x 8 = 96...so the answer must be 96. No written calculation necessary.

 

Do you understand how I did this?

 

Start by watching the video below. Please ignore when it says complete questions 1 - 4 etc. as we are not using the White Rose worksheets. Then, log in to the Power Maths textbook to complete today's Discover and Share pages before moving on to your independent work below. You can complete the TT section if you wish but please do not spend too much time on this - no more than 10 minutes.