What should be added to 7 4/15 to get 8 2/5
Answers
Explanation:
Let n = the unknown number.
The question: "What should be added to 2/5 to get -3/7?" can be translated mathematically into the following equation:
2/5 + n = -3/7
2/5 - 2/5 + n = -3/7 - 2/5
0 + n = -3/7 - 2/5
Since 35 is the lowest common multiple (LCM) of denominators 5 and 7, we can use this information to manipulate the right side of the equation in order to simplify things as follows:
0 + n = -3/7(1) - 2/5(1)
n = -3/7(5/5) - 2/5(7/7)
= [(-3)(5)]/[(7)(5)] - [(2)(7)]/[(5)(7)]
= [-15/35] - [14/35]
= -15/35 - 14/35
= (-15 - 14)/35
= -29/35
CHECK:
2/5 + n = -3/7
2/5 + (-29/35) = -3/7
2/5(1) + (-29/35) = -3/7
(2/5)(7/7) + (-29/35) = -3/7
14/35 + (-29/35) = -3/7
[14+ (-29)]/35) = -3/7
-15/35 = -3/7
-3/7 = -3/7
Therefore, n = -29/35 is the number that needs to be added to 2/5 to get -3/7.
Hope this helps. The question will be easier when we take the number as x or we can solve it directly.
