You can add any fractions with like denominators by simpling adding the numerators (the tops of the fractions) and keeping the denominator (the bottoms of the fractions) the same.
In this case 7/10 +5/10 =12/10.
An improper fraction is any fraction where the numorator (top) is a larger number the the denominator (bottom). To simpliy an improper fraction you divide the numorator by the denominator.
12/10 simplifed would be 12 divided by 10. (I always tell my student to just think of a fraction bar as a division symbol since that is really all it is)
10 goes into the number 12 one time so our whole number is 1. We have a remainder of 2 so that becomes the numorator (or the top) of our new fraction. The denominator does not change. So our mixed number is now 1 and 2/10.
However, we are not done yet as the answer is not simplifed. Simplified fractions are fractions where the numorator and denominator share no factors in common. Since 10 and 2 both have a factor of 2 (2x5=10 and 2x1=2) we can divide both the numerator and denominator by the number 2 to further simplify our fraction.
2 goes into 2 one time so our new simplified numorator is 1. 2 goes into 10 five times so our simplified new denominator is 5. So our fractional part of our mixed number simplifes to 1/5.
When we put our simplifed fraction together with the whole number we found earlier you get a final answer of 1 and 1/5.
You can use these same steps to reduce and simplify any improper fractions! Good luck!