Apparently, nines are the hardest to grasp for primary school children. If only they’d learned how to cheat like me, says Adrian Chiles
Apparently, nines are the hardest to grasp for primary school children. If only they’d learned how to cheat like me, says Adrian Chiles
1-9 by 9 is easy though.
Take the first number, subtract 1 from it, and that will be your 10’s place. Your 1’s place with be whatever that first number needs added to it to get to nine.
Example… 7x9. 7-1= 6, so 60. 9-6=3. Answer is 63.
Another fun math trick while we’re at it. If you want to know if a number is divisible by 3, just add up all the digits, and if that number is divisible by 3, then so is your original number. 3135…3+1+3+5=12, so 3135 is divisible by 3.