How can you use place value when using partial quotients?

What are the domain and range of f(x)=[1/5]x

Emily convinced her mom to buy a giant box of her favorite cereal. her mom doesn't think the box will fit on their shelf. the volume of the box is 1000 cm^3 . the base of the box is 25 cm by 10 cm

What is the order of these fractions from least to greatest 2/3 7/10 5/8 65/500