Ugh I realllyyy need help! The marking period is almost over and I have a mth test tomorrow! I failed all the other tests and I really need to get over a 90 to get a good average grade. I understand all the material on the test except one. I don't get how you add or subtract negative and positive fractions. I get confused with all those signs. Also how do I multiply them? Please helpp
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I am assuming that your trouble is with one being positive and the other negative, and that you know how to add, subtract and multiply them if both are positive numbers.
Ok, now let's see how you to do it if one is positive and the other is negative:
Addition:
If both are negative -
1. Just ignore the signs and add the values and then put a minus sign in front of it. You're done. Cool?
If one is positive and the other is negative -
1. Just ignore the sign and subtract smaller value from the bigger one.
2. If the bigger value is the positive number, then you are done. You answer from step 1 is the final answer.
3. If the bigger value is the negative number, put a minus sign in front of your answer from step 1.
Subtraction:
1. Convert subtraction to addition by negating the second number (i.e., if the second number is positive, change it to negative and if it was negative change it to positive).
2. Then add the numbers following the steps given for addition.
In other words:
a - (-b) = a + b and a - b = a + (-b)
For example:
1/2 - 1/4 = 1/2 + (-1/4) = 1/4
1/2 - (-1/4) = 1/2 + 1/4 = 3/4
Multiplication:
This is even simpler.
1. Just ignore the signs and multiply the numbers.
2. If both the numbers are the same sign(both positive or both negative), you are done. Answer from step 1 is your final answer.
3. If one is positive and the other is negative(doesn't matter which one), simply put a minus sign in front of your answer from step 1. Done.
Ok, now let's see how you to do it if one is positive and the other is negative:
Addition:
If both are negative -
1. Just ignore the signs and add the values and then put a minus sign in front of it. You're done. Cool?
If one is positive and the other is negative -
1. Just ignore the sign and subtract smaller value from the bigger one.
2. If the bigger value is the positive number, then you are done. You answer from step 1 is the final answer.
3. If the bigger value is the negative number, put a minus sign in front of your answer from step 1.
Subtraction:
1. Convert subtraction to addition by negating the second number (i.e., if the second number is positive, change it to negative and if it was negative change it to positive).
2. Then add the numbers following the steps given for addition.
In other words:
a - (-b) = a + b and a - b = a + (-b)
For example:
1/2 - 1/4 = 1/2 + (-1/4) = 1/4
1/2 - (-1/4) = 1/2 + 1/4 = 3/4
Multiplication:
This is even simpler.
1. Just ignore the signs and multiply the numbers.
2. If both the numbers are the same sign(both positive or both negative), you are done. Answer from step 1 is your final answer.
3. If one is positive and the other is negative(doesn't matter which one), simply put a minus sign in front of your answer from step 1. Done.