12 Useful Math Hacks That They Didn’t Teach You In School

Matematika itu mudah. mudah asal tahu bagaimana cara mengakalinya.
trik matematika berikut ini dapat Anda pelajari dengan mudah ..^^

After finding these math hacks, I’m convinced that all those years of being forced to struggle through math class really was just a torture ploy created by evil math teachers everywhere. Check out these amazing math tips and you’ll agree! Watch out though, you may just unleash the inner math whiz you never knew was in you…

1. How To Convert Fahrenheit to Celsius

As if it was this simple all along…

via reddit/u/quaxon

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2. How To Multiply Large Numbers In Your Head

Who knew?

3. How To Multiply By 11

Finally! I can now multiply more than single digits by 11 in my head.

4. Secret To Remembering The Numbers In Pi

Also a cool party trick.

5. How To Find Fractions Of Whole Numbers

6. How To Figure Out What Day Of The Week Falls On What Date…

You might be confused looking at the picture below, but the math is actually quite simple (albeit a bit elaborate). You’ll need the codes HERE, which will help you master this.

July simply has a code of 5.
20th is 6 because 7 goes into 20 twice, which is 14. 20 – 14 = 6.
2069 is 2 because the leap year code of 2068 is 1 and 2069 is 1 year after, so that’s 2.

The math can be difficult at first because there are a lot of codes, but it works out incredibly well once you pick it up. Here’s a separate example:

January 3, 2014 is a Friday, right?

So, January, according to the table, is 6, and we handle days by using multiples of 7. We don’t need to, so it’s actually just 3 in this case. Next we need to know the closest leap year, which was 2012. That has a year code of 1 and 2013 is 2 years after, so 3 again.

We get 6 + 3 + 3 = 12 – 7 = 5! FRIDAY!

7. How to Add And Subtract Fractions

8. How To Figure Out Multiples Of Nine

Just count up in the tens column and down in the ones column.

9. How To Use Your Hands For 5, 6, and 9 Times Tables

Click HERE for more detailed instruction…

via instructables / misko13

10. How To Figure Out Percentages

via Twitter / @LifeHacks

11. How To Remember Which Sign Is Greater Than and Which Is Less Than

Alligator always eats the bigger number!

via ducksters

12. Use Lines To Multiply

via school-exercise-books