If you have a large number to multiply and one of the numbers is even, you can easily subdivide to get to the answer:

64 x 62.5, is the same as: 

32 x 125, is the same as:

16 x 250 is the same as:

8 x 500 is the same as:

4 x 1000 is the same as:

2 x 2000 = 4000

Trick 2

Dividing by 5

It is very simple to divide a large number by five. All you to do is multiply by 2 and move the decimal point:

195 / 5

Step1: 195 * 2 = 390
Step2: Move the decimal: 39.0 or just 39

2988 / 5

Step 1: 2988* 2 = 5976
Step2: 597.6

Subtracting from 1,000

To subtract a large number from 1,000 you can use this basic rule: subtract all but the last number from 9, and then subtract the last number from 10:

1000-648

step1: subtract 6 from 9 = 3
step2: subtract 4 from 9 = 5
step3: subtract 8 from 10 = 2

Answer: 352

Trick 4

Find 7 % of 300. Sound Difficult?

Percents:  Let us first understand the word “Percent.”

The first part is PER , as in 10 tricks per listverse page.

PER = FOR EACH.

The second part of the word is CENT, as in 100. Like Century = 100 years. 100 CENTS in 1 dollar… etc. Ok… so PERCENT = For Each 100.

So, it follows that 7 PERCENT of 100, is 7. (7 for each hundred, of only 1 hundred).
8 % of 100 = 8. 35.73% of 100 = 35.73
But how is that useful??

Back to the 7% of 300 question. 7% of the first hundred is 7. 7% of 2nd hundred is also 7, and yep, 7% of the 3rd hundred is also 7. So 7+7+7 = 21.

If 8 % of 100 is 8, it follows that 8% of 50 is half of 8 , or 4.

Break down every number that’s asked into questions of 100, if the number is less then 100, then move the decimal point accordingly.

EXAMPLES:

8%200 = ? 8 + 8 = 16.
8%250 = ? 8 + 8 + 4 = 20.
8%25 = 2.0 (Moving the decimal back).
15%300 = 15+15+15 =45.
15%350 = 15+15+15+7.5 = 52.5

Trick 5

Flip Percent Trick

Also it’s useful to know that you can always flip percents, like 3% of 100 is the same as 100% of 3.

35% of 8 is the same as 8% of 35.

Answer:- 2.8