How many hours a day do you play computer games?

1. I play computer games for 1-2 hours.

2. I play computer games 1-2 hours.

3. I play computer games for from 1 to 2 hours.

4. I play computer games from 1 to 2 hours.

5. I play computer games for 1 through 2 hours.
-------------------------
Which answers are correct? Can we put 'from' before '1'? Can we read 'through' instead of 'to'?

1 is best.

2 and 4 are OK.
3 and 5 not correct.

The most common expression for this is as follows.
I play computer games for one or two hours a day.

All the options you provided can be correct answers, but there are slight differences in phrasing. Let's go through each option:

1. "I play computer games for 1-2 hours." This sentence is grammatically correct and accurately conveys that you play games for a duration of 1 to 2 hours.

2. "I play computer games 1-2 hours." This sentence is also grammatically correct and implies the same meaning as the first option. Some may argue that it's more common to use "for" before the time range, but this phrasing is still acceptable.

3. "I play computer games for from 1 to 2 hours." This sentence repeats the word "for" before "from," which is not necessary. You can remove the second "for" to make it grammatically correct: "I play computer games from 1 to 2 hours."

4. "I play computer games from 1 to 2 hours." This sentence is grammatically correct and accurately denotes that you play games for a duration between 1 and 2 hours. The phrasing is clear and concise without unnecessary repetition.

5. "I play computer games for 1 through 2 hours." This sentence is also grammatically correct and means the same as the previous options. Using "through" instead of "to" is acceptable in this context and conveys the same time range.

In summary, options 1, 2, 4, and 5 are correct, while option 3 can be slightly improved by removing the second "for" before "from." Additionally, using "through" instead of "to" (as in option 5) is acceptable.