Add, Subtract and Multiply Fractions

1) What is the sum of these fractions in lowest terms? Don't forget that you need a common denominator.

2) What is the sum? Make sure you get common denominators first.

3) What is the difference? You need a common denominator.

$$\frac{2}{5}-\frac{1}{4}$$   4) Don't forget a common denominator

$$\frac{1}{3\ }\times\ \frac{3}{5\ }=$$   5) Multiply straight across and then SIMPLIFY

$$\frac{4}{5}\times\frac{1}{4}=$$   6) Cross cancel first

3/7 x 21/24 - 7) You can double cross cancel first

$$\frac{1}{5}\times2\frac{1}{4}$$   8) Change mixed numbers to improper first

$$\frac{1}{8}\times1\frac{1}{5}$$   9) Change mixed number to improper and cross cancel if you can

After spending a week on fractions, I am still unclear about... (choose all that apply)