Write the fraction $\frac{3}{10}$310 as a decimal.
Write the fraction $\frac{5}{10}$510 as a decimal.
Write the fraction $\frac{1}{2}$12 as a decimal.
Write the fraction $\frac{4}{5}$45 as a decimal.
Apply and extend previous understandings of multiplication and division and of fractions to multiply and divide rational numbers.