I think the best way is to see 12 as one ten and two units. Multiplying numbers by 10 is an easy first step and something that children will have been repeating, practicing, chanting and hopefully knowing with understanding since they were 6 or 7 years old.
So how will this help them with multiplying by 12? If you ask children to visualise this as 'multiplying by 10 and then multiplying by 2' then the process of partitioning (or using partial products) makes the quick recall easier.
For example, 7 x 12 is the same as 7 x 10 added to 7 x 2. The calculation of 70 + 14 is probably easier than retrieving the whole fact from memory.
I word this in a slightly different way, once I've explained the process above. You can recall facts for the 12 times table by multiplying your number by 10 then adding double that number.
So...
6 x 12 ⇒ 60 + double 6 ⇒ 72...
8 x 12 ⇒ 80 + double 8 ⇒ 96...
Try it, it works every time! Don't say it is a 'trick' - it is using the rules of our wonderful number system!
For example, 7 x 12 is the same as 7 x 10 added to 7 x 2. The calculation of 70 + 14 is probably easier than retrieving the whole fact from memory.
I word this in a slightly different way, once I've explained the process above. You can recall facts for the 12 times table by multiplying your number by 10 then adding double that number.
So...
6 x 12 ⇒ 60 + double 6 ⇒ 72...
8 x 12 ⇒ 80 + double 8 ⇒ 96...
Try it, it works every time! Don't say it is a 'trick' - it is using the rules of our wonderful number system!
