Question

9/10-3/4

Answer 1

Here you're combining two fractions (that is, subtracting one from the other).
To combine fractions with different denominators, we must determine the lowest common denominator (LCD). Here, your denominators are 10 and 4. What's the LCD?

Hint: factor both 10 and 4 (separately).

Answer 2

5 and 2?

Answer 3

@mathmale

Answer 4

factor both 10 and 4:
10=2*5
4 =2*2
So, 10 and 4 have the common factor. But 10 also has a factor, 5, that is not in the other denominator.
Also, 4 has a factor, 2, which is not in the other denominator.

You must find a way to modify

the given two fractions so that both fractions have the same denominator.

Care to give that a try?

Answer 5

Do you change it to a reciprocal ?

Answer 6

No, not to a reciprocal.

In summary, you have 9/10-3/4.
It's easier to work on this if you rewrite this as\[\frac{ 9 }{ 10 }-\frac{ 3 }{ 4 }\] and this can be re-written again as \[\frac{ 9 }{2*5 }-\frac{ 3 }{ 2*2 }.\]

Answer 7

The LCD is found by taking the common factor, 2, and multiplying that by 2 (from the 2nd fraction's denominator) and also by 5 (fron the 1st fraction's denominator).

Experiment. What do you think you should do next, to re-write these fractions with the same denominator, so that you can combine them?

Answer 8

ok I wrote it down...

Answer 9

is the answer 3/20?

Answer 10

@mathmale

Answer 11

Your denominator, 20, is correct! Nice work.
But I'd rather that you show me how you got 3/20 before I give you feedback on that.