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June 29th, 2019, 05:11 PM   #1
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Math Challenge

How do you add up 27 and 48 in your head?
My method
20 + 40=60, 60 +7=67, 67+8=75. What is your method?
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June 29th, 2019, 06:34 PM   #2
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For me, it goes, "sixty; sixty-seven; sixty-tenty-five," which is more-or-less the same thing.
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June 29th, 2019, 08:30 PM   #3
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Math Focus: Wibbly wobbly timey-wimey stuff.
Quote:
Originally Posted by NinjaX3 View Post
How do you add up 27 and 48 in your head?
My method
20 + 40=60, 60 +7=67, 67+8=75. What is your method?
An abacus.

-Dan
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June 29th, 2019, 09:17 PM   #4
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60+15 = 75
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June 30th, 2019, 12:00 PM   #5
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Cool! that's how you solve that problem in your mind.

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June 30th, 2019, 12:02 PM   #6
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Quote:
Originally Posted by DarnItJimImAnEngineer View Post
For me, it goes, "sixty; sixty-seven; sixty-tenty-five," which is more-or-less the same thing.
That is interesting, how you came up with that. I hadn't thought of it that way. Brilliant!

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Last edited by skipjack; July 1st, 2019 at 04:08 PM.
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June 30th, 2019, 12:03 PM   #7
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Quote:
Originally Posted by topsquark View Post
An abacus.



-Dan
You could use that interesting.

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June 30th, 2019, 04:48 PM   #8
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Quote:
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An abacus.
In your head? Time for an upgrade!

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June 30th, 2019, 05:14 PM   #9
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$27+48 = 3 \cdot 9+3 \cdot 16 = 3(9+16) = 3(25) = 75$

it's how Ramanujan would do it ...
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June 30th, 2019, 05:24 PM   #10
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$27+48 = 3 \cdot 9+3 \cdot 16 = 3(9+16) = 3(25) = 75$



it's how Ramanujan would do it ...
Excellent, That is another way of doing it.

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