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heres a trick to speed add and 2 digit number by 11 les say you take 73 X 11 now we know its 803 take the 7 and 3 and split it fot its 7 3 and them up its ten add the 1 to the 7 it makes 8. 803.. or lets take 27X11 its 297 split the 2 and 7 and add them 2 7 2+7=9 297 get that :D
if you need two digits X 9 like 45X9 round it to 450 and subtract the 45 405 easy
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