Something for slightly older children. The 6,7,8 and 9s are usually harder to learn and this method might appeal to children who already know the 2-5 tables.
Hold your hands in front of you palms up. Your pinkys represent #6, Ring finger =7, Middle is 8, pointer is 9, and 10 is represented by thumbs.
Put the fingers that represent your problem together. For example 8x8 = middle fingers touch.
For each finger that is touching and each finger below count ten.
For example with 8x8, six fingers (two touching, and two on each hand below that=60)
Count the fingers above the two touching on each hand, separately.
Multiply those two numbers. With 8x8 you have two on each hand. (2x2=4).
The 9s is a neat trick and is much easier to learn. All multiples of 9 have a digit sum of 9. Take 23121 if you add the digits together you get 9 so it is divisible by nine. Another example 99 - calculate digit sum as follows 9+9=18 1+8=9 basically you continue until your get to a single digit. Numbers with digit sums of 3,6 or 9 are divisible by 3 and divisible by 6 if the number was even.
The method above can be extended to calculate the 12,14,16 18 tables
Example take 8 multiplied by 16 Calculate as though calculating 8 times 8 so your middle fingers are touching. Simply double the tens and units to get the correct answer.
Did you see my reply to your post regarding memory techniques?
Thank you for the good info on math tricks! I’d heard of adding the digits of a number to see if it is divisible by nine in Math-U-See, which my older boys are doing. I had to go and show them the other trick. :laugh: Now I’ll have to tell them about doubling to do 12, 14, 16 and 18.
I started watching the video clip on memory techniques, then got distracted. I’ll have to go back and watch it. Thanks for asking .
