Khan Academy Wiki

The Writing and interpreting decimals exercise appears under the 5th grade (U.S.) Math Mission, Arithmetic essentials Math Mission, Pre-algebra Math Mission and Mathematics I Math Mission. This exercise introduces the correct way to interpret decimal numbers.

Types of Problems[]

There are three types of problems in this exercise:

  1. Write the number described: This problem has a number written in English. The user is expected to write the number in it's decimal form.
    Writeinterpdec

    Write the number described

  2. Select the expanded form: This problem has a decimal number written. The user is asked to select the correct expanded form of the number from a multiple choice list after possibly performing a basic operation.
    Writeinterpdec2

    Select the expanded form

  3. Change expanded into decimal: This problem states a number in expanded form and possibly a basic operation. The user is asked to write the correct decimal number in the available space.
    Writeinterpdec3

    Change expanded into decimal

Strategies[]

This exercise is medium to get accuracy badges because the problem changes often. The speed badges are easy once user gets over the fact that it changes on every problem because the timing tolerance is decent.

  1. The operations that are sometime required are multiplying or dividing by ten.
  2. Don't click too quick, user really needs to reread the question to make sure they are answering the questions that is being asked.
  3. Most of the time the answers are written in correct order of their places, so it is relatively simple to rule out obviously wrong answers.

Real-life Applications[]

  1. Decimals appear in every day media to display information to consumers.
  2. Decimals are very common in shopping. Price tags, food labels, and receipts all contain decimals.
  3. At gas pumps, decimals are used to show how much gas is pumped and much it costs per gallon.