Li does one quarter of her homework before dinner and a further one third after dinner. what fraction of her homework remains undone?

5/12

Step-by-step explanation:

Since we are adding fractions, we have to find the least common demoninator, which means the denominators (the bottom part of the fraction) are equal. To do this, we can take each denominator and multiply them together. 4x3=12, so the least common denominator is 12. We then multiply the numerator by however many we had to multiply the denominator. So to get to 12, 4 (the denominator) must be multiplied by 3, so 1 (the numerator) must be multiplied by 3, giving us 3/12. We do the same thing to the other fraction, so for 3 (the denominator), we multiply by 4, so 1 (the numerator) must be multiplied by 4, giving us 4/12. Then we add the two together and we get 7/12. We then have to subtract 7/12 from 12/12, giving us 5/12.

Answer: The answer is 5/12 of her homework left.

Step-by-step explanation:

She first did 1/4 and then 1/3. Adding them together gives a total of 7/12 of it being completed. The part where it's unfinished is 5/12, the answer.