What's the quickest and smartest short cut to multiply any number by 360 and by 365? Thanks!

Bain BCG HelpASisterOut Math problem Mck McKinsey RolandBerger
New answer on Sep 23, 2020
2 Answers
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Anonymous A asked on Sep 22, 2020

This is helpful for market size

(edited)

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Udayan
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replied on Sep 23, 2020
Top rated Case & PEI coach/Multiple real offers/McKinsey EM in New York /12 years recruiting experience

Anything that ends in 0 - if you are multiplying by it automatically add 0 and multiply by what comes before it

So for 360*5 - make it 50X36

Then I like doing two separate additions to solve it so

50*36 = 50*30 + 50*6

You can always group 0s together so 50*30 = (5*3)*100 = 1500

and 50*6 = (5*6)*10 = 300

so 50*36 = 1500+30 = 1800

Hope this helps,

Udayan

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Ian
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updated an answer on Sep 22, 2020
#1 BCG coach | MBB | Tier 2 | Digital, Tech, Platinion | 100% personal success rate (8/8) | 95% candidate success rate

First, you should learn long multiplication.

Else, I would split 365 up and do:

333 x 3 + 32 x 3

(Leaves 120)

1000 x 120 + 100 x 120

=

120,000 + 12,000

= 132,000

Then, remember we rounded up by 1 and 4, respectively. So 5 x 120 = 600

132,000 - 600

= 131,400

(edited)

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Udayan

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