please tell me how to add fractions with different denominators.

Question

chaise · Answer

You must do what is called "cross multiply, the rule is given by the following algebraic expression:

$$\frac{a}{b}+\frac{c}{d}=\frac{ad+bc}{bd}$$

anonymous · Answer

huh? i am in fourth grade and i am not good at math. please further explain.

anonymous · Answer

please hurry up.

chaise · Answer

For example:

If we want to add the following two fractions:

$$\frac{3}{4}+\frac{6}{2}=\frac{3*2+4*6}{4*2}$$

$$\frac{6+24}{8}=\frac{30}{8}$$

Do you see how this works?

anonymous · Answer

yes. thank you so much!

anonymous · Answer

R u  a math teacher or something? ;)

chaise · Answer

I am not, ahah, I'm just an amateur enthusiast of mathematics! 

If you have anymore questions feel free to ask! I'll do my best to answer them in a clear and concise manner.

anonymous · Answer

Thank you.

anonymous · Answer

Is it normal for fourth graders to be learning adding fractions? Am I behind?

chaise · Answer

I guess it depends on your country of origin, but this method of adding fractions isn't taught to many fourth graders, as far as I'm aware. If you understand this it is great! 

There is another way in which your teacher may teach you to add fractions, and that's by making the denominators the same.

anonymous · Answer

ok