1/5 of 20 = 4
1/5 of 35 = 7
1/5 of 25 = 5
1/5 of 10 = 2
1/5 of 500 = 100
Method 1: 1/5 of 20 is 1/5 times 20 which you can solve for by multiplying the 1 by 20 and then dividing by 5 so 20/5=4.
Method 2: 1/5 of 20 is 1/5 times 20 so what you can do is automatically look at it and say that 5 is divisible by 20 and so using the cross method you can eliminate the 1 and just do 20/5=4.
You can either of the processes to figure out all of them.
