SHORT TRICK ON PERCENTAGE.

✓FINDING 16-2/3% OF A NUMBER Rule: Divide the given number by 6. If the given number is odd, the answer will contain a fraction. See Short Cut 71 for the rule for divisibility by 6. Find 16-2/3% of 132.00 132 ÷ 6 = 22 Therefore 16-2/3% of 132 = 22.00 Answer 

✓FINDING 33-1/3% OF A NUMBER Rule: Divide the given number by 3. What is 33-1/3%of 12?

Divide by 3. 12 + 3 = 4 Therefore 4 is 33-1/3% of 12. 

✓FINDING 37-1/2% OF A NUMBER. Rule: Multiply the given number by 3 and divide the result by 8. Either operation may be performed first; the answer will be the same. For example: Find of 7,216. Multiply by 3. 7,216 x 3 = 21,648 Divide by 8. 21,648 ÷ 8 = 2,706 Therefore 37-1/2% of 7,216 = 2,706 Answer If the order of operation were changed, 2, 706 would again be obtained. This time, divide by 8 first. 7,216 ÷ 8 = 902 (This can be obtained almost by inspection.) Next, multiply by 3. 902 x 3 = 2,706 It is evident that in this particular example the second order of operation is the one that produces the answer with the least mental effort. 

✓FINDING 62-1/2% OF A NUMBER Rule: Move the decimal point one place to the right and divide by 16. Dividing by 16 is not as formidable as it may seem at first. As a matter of fact, it can usually be done easier in two steps. Dividing the given number by 2 and then dividing the result by 8 is one way of simplifying this division. Another way is to divide the given number by 4 and then divide the result by 4 again. Both methods will be demonstrated in the example below: but first. division by 16 will be shown. Find of 512. Move the decimal point one place to the right. 512.0 becomes 5,120. Divide by 16. 5,120 16 = 320 Answer The same number, 5,120, will be divided by 2 and the result divided by 8. 5,120 ÷ 2 = 2,560 2,560 ÷ 8 = 320 Answer Next, the number will be divided by 4 and the result again divided by 4. 5,120 = 4 =1,280 1,280 ÷ 4 = 320 Answer In a given problem, at least three choices are open, depending on what the given number is and how easily it can be divided by 2, 4, or 8. 

✓FINDING 66-2/3% OF A NUMBER Rule: Divide by 3 and subtract the result from the given number. Find 66-2/3%of 75. Divide by 3 and subtract the result from the given number. 75÷ 3 = 25 75 - 25 = 50 Therefore 50 is 66-2/3%of 75. 

✓FINDING 87-1/2% OF A NUMBER Rule: Divide the given number by 8 and subtract the result from the given number. By carrying on the division under the given number, the subtraction can easily follow. 

Find 87-1/2% of 37.52. Divide the given number by 8. 8) 37.52 Given number — 4.69 Quotient

32.83 Difference Thus 87-1/2% of 37.52 = 32.83 Answer