How do you write #10# #5/12# as an equivalent improper fraction?

1 Answer
Mar 22, 2016

#color(brown)("This has been shown using first principles. The ")##color(brown)("shortcut methods do not explain what is happening.")#

#" "color(magenta)(10 5/12 = 125/12)#

Explanation:

Given:#" "10 5/12#

#color(blue)("Shortcut method - with proper sign")#

#10 5/12 = (10xx12)/12+5/12color(blue)( =125/12)#

'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#color(blue)("First principles with full explanation")#

This can be written as:#" " 10+5/12#

Although not normally done, it is perfectly correct to write #10" "as" " 10/1#

So we now have:#" " 10/1+5/12#

To be able to add the top numbers (numerator) directly the bottom numbers (denominators) need to be the same.

If we multiply a number by 1 then its value is not changed and it still looks the same.

However, the value of 1 can be presented in many ways. For example #1=12/12#

Consider the #10/1# Let us multiply it by #1=12/12# so we have

#" "10/1xx12/12=(10xx12)/(1xx12) = 120/12#

The #120/12# is exactly the same value as #10/1# but it just looks different.

So now we can write

#" "10 5/12 = 10/1+5/12 = color(brown)(120/12+5/12)#

#" "color(magenta)("Now you can directly add the top numbers.")#

#" "120/12+5/12 =(120+5)/12 = 125/12#

#" "color(magenta)(10 5/12 = 125/12)#