SOLUTION: How do i solve 49 times 19... Mentally?

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Question 745006: How do i solve 49 times 19... Mentally?
Found 2 solutions by stanbon, Alan3354:
Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website!
How do i solve 49 times 19... Mentally?
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49*19 = (50-1)(20-1) = 1000-50-20+1 = 931
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Cheers,
Stan H.

Answer by Alan3354(69443) (Show Source):
You can put this solution on YOUR website!
How do i solve 49 times 19... Mentally?
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There are many ways for this one.
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= 19*7 then *7
= 19*50 then -19 the best for this one, imo
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Another method, not so attractive for this one is
Get the average = (49 + 19)/2 = 34
Diff between ave and numbers = 15
49*19 = avg^2 - diff^2 = 1156 - 225
This works well for a lot of them, not so good for this one.
eg, 37*39 = 1443 easily (if you know what 38^2 is)