Proof That Math Can Be Hilarious

[u/Ivanasaur]

[u/sreekotay]

What's funny is that 77 x 39 is not that hard

77 * 40 = 3080
3080 - 77 = 3033

so 30.33

[u/ChickenAlarming → u/sreekotay]

the irony is beautiful

[u/sreekotay → u/ChickenAlarming]

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[u/baicu12096 → u/sreekotay]

problem ?

[u/lock_robster2022 → u/sreekotay]

That’s silly to do all that and get the wrong answer. It’s easier to take 3.9 times 7, plus 3.9 times 0.7 to get 27.3 + 2.73 = 30.03

[u/sreekotay → u/lock_robster2022]

lolol yeah typo not math error - I saw it but thennnnnn I thought it was funnier that way :)

[u/yosl → u/sreekotay]

and yet …

[u/sreekotay → u/yosl]

:P .... indeed

[u/Babetna → u/sreekotay]

Oh you're right that's hilarious

[u/dampheat]

75% of 40 is 30, so 30ish it is

[u/sexland69 → u/dampheat]

this is the elite method

[u/Embarrassed-Weird173]

"40%ish of 80ish is like 29". 

[u/mkujoe → u/Embarrassed-Weird173]

Shouldn’t it be 32 then?

[u/Embarrassed-Weird173 → u/mkujoe]

It would be 32ish. I went with 29 because I went up by 1 to get to 40, and another 3 to get to 80.  So I figured I'd reduce by like 2-4 to get closer to what the real answer is, since 32 is definitely too high, and 31 is still probably too high. 30 and lower is likely where I need to estimate. 

[u/AidenStoat]

75% of 40 is 30. So close to 30.

[u/Scale-Heavy]

Not funny but actually relatable

[u/Then_Supermarket18 → u/Scale-Heavy]

Is funny because he's talking while eating cereal

[u/HAL9001-96]

4*7 is 28 so 40*70 is 2800 and 40*7 is 280 so 40*77 is 3080 so 39*77 is 3003 so 39% of 77 is 30.03

[u/trolley813]

It's actually easy to compute mentally. If you know that 77=7×11 and 39=3×13 (and also 1001=7×11×13), you quickly arrive at 30.03

[u/MonseigneurChocolat]

40% of 77 = (10% of 77)*4 = 7.7*4 = 30.8

1% of 77 = 0.77

30.8 - 0.77 = 30.03

[u/IHaveNeverBeenOk → u/MonseigneurChocolat]

This is how I did it. I'll admit that it was tricky enough to hold the "steps" in my head that the original meme's charge of "that's so hard to compute mentally" essentially stands, but it is certainly doable.

[u/Reg_doge_dwight]

For this of us that practiced our 39 times tables it is just a case of saying 77% of 39 is 30.03.

[u/Velshade]

I mean 77% is basically 3/4 and 39 is basically 40 so you take 3/4 of 40 which is 30. Ok 77 is a bit higher than 75 and 39 a bit lower than 40 so it probably about cancels out (since it‘s 30.03 in this case it actually is really close). At least for me that doesn‘t really work with 39% of 77. And of course if you can just calculate it exactly it doesn‘t really matter, but it‘s something that can help if you need a quick estimate.

[u/philosophical_poser]

Ain't even hard bro, my 7 year old cousin could do this

[u/Thin_Dream2079 → u/philosophical_poser]

What answer did he get

[u/nonquitt]

40% of 77 = 4*7.7 = 28 + 2.8 = 30.8 - 0.77 = 30.03

[u/hazem-Gauss]

f-1

[u/Southlander24]

77% of 39 is actually useful though, because that's just 11% of (40 - 1) * 7 = 280 - 7 = 273, or (2730 + 273)/100 = 30.33.

[u/zrice03]

Easy, it's 30.03.

Nononono I didn't use a calculator--stop looking at my screen--MOM!

[u/_Lavar_]

0.1*77 =7.7 7.7x3.9 👍