so, to explain:
you first have to convert.
1) you make the denominators the same. however, when multiplying to make the denominators the same, you have to multiply the numerator as well.
2) since the problems asks for total cups of sugar, (total meaning you have to add) we add.
1+2= 3 4+9= 13
the denominator stays the same for both fractions through the entire problem after this.
the fraction then looks like
3) since the numerator is larger than the denominator, you subtract the number at the denominator from the one on the numerator. 13-12= 1.
4) since you only had to subtract once before the numerator became smaller then the denominator, 13 divides into 12 once. so, you add one to the whole number.
5) this would make the answer to the question,
6) please read the instructions, it took a while to make and I did it so a random person idk could understand a topic. use it to inderstand this fully. if you need anymore help, just follow me so you can ask any time.