How to make 2.1 into a fraction?

1 Answer
Mar 21, 2018

21/102110

Explanation:

Any constant in the tenths place (the first value after the decimal) can be put over 10:10:

2.12.1

2 and .12and.1 color(blue)("Separate terms")Separate terms

2 and 1/102and110 color(blue)( .1 " is read as 'one tenth'"=1/10).1 is read as 'one tenth'=110

2(1/10)2(110) color(blue)("Now we have a mixed fraction")Now we have a mixed fraction

To simplify this further, we would turn it into an improper fraction (where the numerator > denominator). Consider this explanation of a mixed fraction:

color(red)(a)(color(blue)(b)/color(purple)(c))a(bc)

To turn a mixed fraction into an improper fraction, there are 2 steps:

  1. Multiply color(purple)(c)*color(red)(a)ca
  2. Add the product of (color(purple)(c)*color(red)(a)) +color(blue)(b)(ca)+b
  3. Leave the denominator as color(purple)(c)c

So, now that we know how to turn a mixed fraction into an improper fraction, let's try it:

color(red)(2)(color(blue)(1)/color(purple)(10))2(110)

color(red)(20)(color(blue)(1)/color(purple)(10))20(110) color(blue)(10*2=20)102=20

color(red)21/color(purple)(10)2110 color(blue)(20+1=21)20+1=21

21/202120