Posted by **makhissa** on Tuesday, September 19, 2006 at 5:07pm.

i need help on adding and subtacting rational numbers like -7over12+5 over 6

When adding rational numbers we need a common denominator. We have

-7/12 + 5/6

What is the least common multiple of 12 and 6? After you find that make sure both fractions are expressed as a ratio of some number to the lcm, then add the numerators, or in this case subtract one of them from the other.

ok