well we're doing year 7 fractions and i forgot how to subtract.
i can divide and multiply, but i forgot how to subtract and add!
so this is the sum...
[i cant write a fraction so here you go anyway]
26 over 3
subtract
31 over 5
hope you can help!!!!!
How do i subtract fractions??? please help!!?
2008-08-27 11:19 am
回答 (6)
2008-08-27 11:24 am
✔ 最佳答案
Make denominators equal by finding their LCM and subtract Numerators. Keep the same common denominator. [ Don't subtarct them too!]The "go" id not clear. What is to be subtracted from what?
If 26/3 - 31/5 then it is 130/15 - 63/15 = 67/15.
2008-08-27 11:29 am
26/3-31/5 = (26*5)/15 - (31*3)/15= 130/15- 93/15=37/15= 2 7/15
2008-08-27 7:29 pm
26 / 3 - 31 / 5
130 / 15 - 93 / 15
37 / 15
130 / 15 - 93 / 15
37 / 15
2008-08-27 11:42 am
3 = 3
5 = 5
----------------------
The LCM of 3 , 5 is:
3 x 5
= 15
26/3 - 31/5
= (26 x 5)/(3 x 5) - (31 x 3)/(5 x 3)
= 130/15 - 93/15
= 37/15
5 = 5
----------------------
The LCM of 3 , 5 is:
3 x 5
= 15
26/3 - 31/5
= (26 x 5)/(3 x 5) - (31 x 3)/(5 x 3)
= 130/15 - 93/15
= 37/15
2008-08-27 11:30 am
That would be like subtracting apples from bananas. However 3 and 5 are both factors of 15 (3 x 5 = 15). So change each fraction into 15Th's and they can be subtracted. Multiply 26/3 x 5/5 = 130/15 and 31/5 x 3/3 = 93/15. Notice that multiplying by 5/5 or 3/3 is like multiplying by 1 and does not change the value but does change the denominator to what you need.
2008-08-27 11:24 am
26/3 - 31/5 = (26*5)/15 - (31*3)/15 = 130/15 - 93/15 = 37/15
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