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Sun 27 May, 2007 08:41 pm
My nephew cant memorize timetable 9, is there any easiest way....
Subtract one from the number being multiplied by nine, take the result and it's the first number of the answer. Then subtract 9 by this number and the result is the second number.
e.g.
9x9
9-1 = 8
9-8 = 1
Answer: 81
9x5
5-1 = 4
9-4 = 5
Answer: 45
Another way is by jumping up to 10x then subtracting the extra
9 x A = (10 x A) - A
eg
9 x 9 can be deduced by knowing that 10 x 9 = 90...then subtract that extra 9 ....81.
This one is handy for larger numbers, such as 9 x 47....10 x 47 = 470.....470-47=423
Having said that....his entire life will be easier if he gets off his lazy butt and memorizes his tables properly now. A good way to do that is for the whole family to chant the 9x table in the car.... all the way to... wherever!
There is no substitute for repetition. Over and over again. flash card. Half cards. Write the sum on a card and the answer on a different card cut the answer card in half horizontally have your nephew guess what the answer might be using the half answer card as a clue.
9
18
27
36
45
54
63
72
81
90
99
108
look at the pattern of the last number, look at the pattern of the first number
Up to ten (9 x 10), if you add the 2 numbers together, you get 9.
09
18
27
36
45
54
63
72
81
90
Jespah's method was the way I memorized them, more or less. If you multiply 9 times 7, your answer will start with one less than 7 (6) and the two digits will equal 9 when added together (6+_?_=9, ?=3).
Of course, he can multiply by 10 (10x7=70) and take one 7 away (70-7=63).