Simplifying Fractions::: I'm going through SAT practice and I forgot some simple math.?

Question

Simplify:

4 - 9/10
-----------
2/3 + 1/2

How do I work this out?

Answer 1

4-9/10-convert to all tenths, so 40/10-9/10=
31/10 which is THREE AND ONE TENTH or 3.1 as a decimal

2/3 + 1/2--needs least common denominator, which is 6 (3 times two)
so 4/6 +3/6=7/6 which is ONE AND ONE SIXTH or 1.166666 as a decimal

Answer 2

find common denominators.

ex: 4 = 4/1= 40/10
40/10 - 9/10 = 31/10

2/3 + 1/2

2/3 = 4/6 (multiply top&bottomg by 2)
1/2 = 3/6 (mult. top & bottom by 3)

4/6 - 3/6 = 1/6

(you only need a common denominator for add/subtracting, not multiplying/dividing)

Answer 3

40/10 = 4

40/10 - 9/10 = 31/10 or 3 and one tenth
----
2/3 = 4/6

1/2 = 3/6

4/6 + 3/6 = 7/6 or 1 and one sixth

Answer 4

4-9/10=31/10
2/3 +1/2=7/6
Simplified=
31/10=93/30
------------------
7/6=35/30
so your answer is 93/35