Question 64994
Find the sum or difference. - 5/14 - (- 9/10)  When you subtract a -, you add.
-5/14+9/10  In order to add or subtract fractions, you need a common denominator, if you don't know that 70 is the smallest number that both 14 and 10 go into evenly, you can factor both denominators.
14=2*7
10=2*5
LCD=2*5*7=70
Whatever you do to the denominators you must do to the numerators.
{{{-5*5/(14*5)+9*7/(10*7)}}}
{{{-25/70+63/70}}}
{{{(-25+63)/70}}}  If the signs aren't the same, subtract the numbers and keep the sign of the biggest number.
{{{38/70}}}  Both numbers are even, so reduce the top and bottom by 2.
{{{19*2/(35*2)}}}
{{{highlight(19/35)}}}
Happy Calculating!!!