i am confuse with how to change percent to number.can anyone explain it?
well the part i don't understand is that when u change a percent to a number,for example 75%=3/4,how can they know that so fast?
2006-11-09 12:25:35 · 8 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
how 12.5% ?
2006-11-09 12:35:03 · update #1
how 12.5% ?
2006-11-09 12:35:05 · update #2
Just put it as a fraction over 100. Then reduce.
75% = 75/100
Now divide top and bottom by 25:
3/4
If you get something like 37.5%, you need to move the decimal and put the amount over 1000.
375/1000
Again divide numerator and denominator by 125, to reduce:
3/8
Here's another example:
87.5%
= 875/1000
= 7/8
However, lots of people have just learned some of the common fractions as percentages:
1/4 = 25%
1/2 = 50%
3/4 = 75%
Definitely memorize these:
Next there are the "thirds"
1/3 = 33.33%
2/3 = 66.67%
And the "tenths"
1/10 = 10%
2/10 = 20% (also 1/5)
3/10 = 30%
4/10 = 40% (also 2/5)
5/10 = 50% (also 1/2)
6/10 = 60% (also 3/5)
7/10 = 70%
8/10 = 80% (also 4/5)
9/10 = 90%
Then you can get fancy and remember the "eighths"
1/8 = 12.5%
3/8 = 37.5%
5/8 = 62.5%
7/8 = 87.5%
Memorization is how you can do it really fast. And turning it into a fraction over 100 is another way you can do it, though maybe not as fast.
2006-11-09 12:29:50 · answer #1 · answered by Puzzling 7 · 0⤊ 1⤋
75%=75 parts out of 100
express as 75/100
simplify to 3/4
75% is really recognizable. If your question is how people can know that so fast, it's just because they've worked with it in the past and perhaps the reason you can't is because you haven't. I know I can recognize 1/8th as a decimal quickly, and a lot of people I know will take an extra moment, but it's only because I've actually had to use it in the past.
2006-11-09 20:30:23 · answer #2 · answered by endersbean3k1 2 · 0⤊ 0⤋
100/4 = 25
3x25 = 75
so
75 = 75%
3/4 = 75%
1/4 = 25%
2006-11-09 20:34:37 · answer #3 · answered by sweetestspazz24 2 · 0⤊ 0⤋
Easy 75% = 75/100
75/100 then reduce - in this case ... 4 is a good number to divide by...
2006-11-09 20:31:28 · answer #4 · answered by Marshall Lee 4 · 0⤊ 0⤋
75% = .75 = 75/100 = [3*25]/ [4*25] = 3/4
Example
40% = .40 = 40/100 = [4*10]/[10*10] = [2*2*10] / [2*5*10] = 2/5
2006-11-09 20:27:44 · answer #5 · answered by bourqueno77 4 · 0⤊ 0⤋
75%=75/100
obviously the GCF is25
dividing Nr and Dr by the GCF
2006-11-09 20:29:19 · answer #6 · answered by raj 7 · 1⤊ 0⤋
No trick to doing it fast, just experience and practice. The math is shown in the previous answer.
2006-11-09 20:31:02 · answer #7 · answered by quint 3 · 0⤊ 0⤋
LIKE EVERYTHING ELSE, PRACTISE. WITH ME , I ALWAYS THINK A DOLLAR. 75C = 3/4THS OF A DOLLAR. IF SOMETHING COSTS 30C , I THINK, WELL WITH TAX THAT'LL BE 1/3RD OF A DOLLAR. ANY HELP? LET ME KNOW IF YOU NEED MORE.
GOD BLESS
2006-11-09 20:30:26 · answer #8 · answered by thewindowman 6 · 0⤊ 0⤋