- #1
dgoodpasture2005
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Mental Multiplication for 2 digit numbers and beyond
1 7
| <---- this is step one... multiply the tens place times each other. =10X10
1 7 X
now we have 100. The next step will be 10X 7 either way you look at it.
17
/ <---- 10 times 7 is 70... we now have a sum of 170.
17
next step will be the same... except we will multiply with the1 in the tens place from the top of the problem diagonally and down to the right with the 7 in the ones place.
17
\ <---- 10 X 7 is 70, we now have 240, all that is left is the ones place
17
1 7
--| <----- 7X7 is 49... 240 plus 49 is 289... you have your answer.
1 7
We're doing it backwards... hope you all enjoy and understand why doing multiplication from left to right is much easier and faster than right to left. Even while adding up your sum there is no carrying over. Practice this... it's fast and effective... show it to teachers, friends, kids, anyone and everyone. Get this out, please. Mental math, bring it into our world once again. :) Do as you must with this... but please review it before you dismiss it! I didn't know where to post it... so I'll leave it here, enjoy everyone!
1 7
| <---- this is step one... multiply the tens place times each other. =10X10
1 7 X
now we have 100. The next step will be 10X 7 either way you look at it.
17
/ <---- 10 times 7 is 70... we now have a sum of 170.
17
next step will be the same... except we will multiply with the1 in the tens place from the top of the problem diagonally and down to the right with the 7 in the ones place.
17
\ <---- 10 X 7 is 70, we now have 240, all that is left is the ones place
17
1 7
--| <----- 7X7 is 49... 240 plus 49 is 289... you have your answer.
1 7
We're doing it backwards... hope you all enjoy and understand why doing multiplication from left to right is much easier and faster than right to left. Even while adding up your sum there is no carrying over. Practice this... it's fast and effective... show it to teachers, friends, kids, anyone and everyone. Get this out, please. Mental math, bring it into our world once again. :) Do as you must with this... but please review it before you dismiss it! I didn't know where to post it... so I'll leave it here, enjoy everyone!
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