Answer:
1) To add two fractions with the same denominator, just add the two numerators keeping the denominator.
Examples:
a) 1/2 + 3/2 = (1+3)/2 = 4/2 We simplify 4/2 = 2/1 = 2
b) 2/5 + 1/5 = 2+1/5 = 3/5
2) To add two fractions that do not have a common denominator, put both fractions on the same denominator.
WARNING: when you multiply the denominator by a number, you must multiply the numerator by the same number.
Example :
1/2 + 5/4 = (1×2)/(2×2) + 5/4 = 2/4 + 5/4 = (2+5)/4 = 7/4
In this example, betting on the same denominator is simple because it suffices to modify the writing of a single fraction.
Another example :
6/5 + 7/4?
Here it is necessary to modify the writing of the two fractions.
6/5 + 7/4=(6×4)/(5×4) + (7×5)/(4×5) = 24/20 + 35/20
Fractions now have the same denominator (20).
We finish the calculation.
6/5 + 7/4=(24+35)/20 = 59/20
CAUTION: Never forget to simplify if necessary