Answer
(7/9)-(8/12) = 1/9
15(1/4)+6(1/2=27(1/4)=(21/4)
48(9/10)-45(4/5)=(36/5)kg
Explanation:
When working with fractions it is easiest to start with a common denominator.
Difference means to subtract:
8:
(7/9)-(8/12) = 1/9
First simplify 8/12 notice how both terms are even. so 8/12 = 2/3 see how 8 and 12 are divisible by 4 so you get 2/3.
Now the question will be (7/9)-(2/3). Now you can find an easy common denominator.
***** Finding the common denominator is important when adding or subtracting fractions*******
This will be (7/9)-(6/9) the common denominator here is 9. Notice how you only need to multiply (2/3) by three. Now the denominators match so you can subtract them easily.
You will get (7/9)-(6/9)=(1/9)
9: Sum means to add and subtracted obviously means to subtract. Remember find a common denominator than simplify. The easiest way todo this is work through the problem one fraction at a time. Remember to follow the order of operation. (In this case + and - are the same order of operations so it doesn't matter what you do first.)
(27/4)
So lets start with the first two 15(1/4)+6(1/2)
The common denominator here is 4 so multiply 6(1/2) by 2
15(1/4)+12(1/4)=27(1/4)
Now lets subtract
27(1/4)-4(3/8)=(27/4)-(12/8) notice the common denominator as 8.
lets multiply(27/4)) by 2
(54/8)-(12/8)=(42/8)
Notice how it divisible by 2
so (42/8) = (21/4)
so
15(1/4)+12(1/4)=27(1/4)=(21/4)
10: 48(9/10)-45(4/5)=(432/10)-(180/5)
Notice common denominator 10 so multiply (180/5) by 2
(432/10)-(360/10)=(72/10)
Notice divisable by 2
so (72/10)=(36/5)