If the two numerators add to an even number (x) then that number and the denominator (10) can both be divided by two leaving you with x/2 over 5 because (x/2)/5 is equivalent to x/10
To explain how you can add two fractions with denominators of 10 and end up with a sum whose denominator is 5, you need to understand that when adding fractions, the denominators must be the same. When the fractions involved have different denominators, you must find a common denominator. In this case, since 5 is a factor of 10, you can use 5 as the common denominator.
First, you need to rewrite each fraction so that they both have a denominator of 5. To do this for a fraction with a denominator of 10, you divide the denominator by 2, and do the same to the numerator to maintain the value of the fraction. For example, if you have "1/10", when you divide the numerator and denominator by 2, you get a fraction of "1/5".
Once both fractions have the same denominator, you can simply add the numerators together. You never add the denominators. The result will be a sum with a denominator of 5, which might need simplification if common factors are present in the numerator and denominator.
To add two fractions with a denominator of 10 and end up with a denominator of 5, you can first add the fractions normally, then simplify the result. For example, 10 3 + 10 2 = 10 5 ; simplifying gives 2 1 . The key is in recognizing that both numerator and denominator can be reduced based on common factors.
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