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# Math for Kids

#### 2017-01-19 Geometry - Direct and Inverse Varation:

Hi Aishwarya,    Direct and inverse variation are not the same as cross multiplying.  They are concepts used in problem solving.    Direct variation is when the independent variable increases proportionally

#### 2017-01-19 Geometry - Percentage:

Hi Aishwarya,    Historically, 1 out of 100 was a convenient ratio for a rate of taxation.  It became a standard concept over time.    Mathematically, a percentage is just a fraction with a denominator

#### 2017-01-16 Basic Math - mental math:

Good question!    Here are some places to read about it...  https://www.quora.com/How-did-Shakuntala-Devi-perform-such-huge-calculations-with-great-speed-and-precision  https://www.quora.com/How-did-Shakuntala-Devi-mentally-calculate-the-23rd-root-of-a-201-digit-number-correctly

#### 2017-01-07 Basic Math - Determing actual age from apparent age of characters:

Hello Julian,    Without additional info there are literally infinitely many possibilities!  The relationship could be (1) linear, (2) quadratic, (3) cubic, (4) exponential, (5) logarithmic,  (6) power

#### 2016-12-29 Word Problems - Rates:

The 39,000 man-hrs is the amount of work done or to be done. So, it could mean 39,000 men work for  1 hour, or 3900 men work for 10 hrs, or 390 men work for 100 hrs, or 39 men work for 1000 hrs, or as