For both of these you want to find a common factor
1. 10(1)- 4(7) the easiest way to do this you multiply 4*10 for a common
10(4) 4(10) factor of 40. You multiply the same number on top and on
10 - 28 = -18 and on the bottom to keep the same value (whatever you do
40 40 40 on the bottom you do on the top). This let's you have the
1. -18/40 same denominator so you can just subtract the numbers.
2. 2(2)- 3(1)
2(3) 3(2)
4 - 3 = 1
6 - 6 6
2. 1/6