Less Obvious Easy 9 TimesTables
Created | Updated Feb 3, 2002
This seem a strange implementation of the 9 times table but this method greatly increases the performance of Year2 students whose brains cannot yet grasp subtraction. This is done by simplifying the great drop in numbers via substituting in 10s to bring the difference to a minimum eg 120-108 = 20-8 = 12 etc. So this results in a two stage calculation of:
(as this is for 8 year olds base 10 is used with only integers)
[Starting At]Tens:
n - (1 plus an additional for every 10 n is worth)
[Starting At]Singles:
(10 plus an additional 10 for every 10 n is worth) - n
As mentioned previously this is known to work with pupils multiplying 8 digit numbers by 9 under 2 seconds at King Edward's Primary School, Nottinghamshire in 1992.
Example:57 * 9 (n is worth 50+ so the bonus is 5)
Tens = 57 - 6 = 51
Singles = 60 - 57 = 3
Answer = 513
(as this is for 8 year olds base 10 is used with only integers)
[Starting At]Tens:
n - (1 plus an additional for every 10 n is worth)
[Starting At]Singles:
(10 plus an additional 10 for every 10 n is worth) - n
As mentioned previously this is known to work with pupils multiplying 8 digit numbers by 9 under 2 seconds at King Edward's Primary School, Nottinghamshire in 1992.
Example:57 * 9 (n is worth 50+ so the bonus is 5)
Tens = 57 - 6 = 51
Singles = 60 - 57 = 3
Answer = 513
