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7th grade · Math · Unit 2 of 20

Decimal Operations

Add, subtract, multiply, divide decimals

What your child practices

All four operations with decimals, estimating to check answers, ordering decimals, and money problems such as unit prices.

New York State Learning Standards learning standard: NY-7.NS.3; NY-7.EE.3 · computing with decimals and solving multi-step problems with rational numbers

How we explain it

Children can open this short lesson before they practice.

  1. To add or subtract, line up the decimal points.
  2. Fill empty places with zeros so the numbers match.
  3. Then add or subtract like whole numbers.

Example: 3.45 + 2.8 = ? Write 2.8 as 2.80 and line up the points. 3.45 + 2.80 = 6.25. Answer: 6.25

Decimal Operations in New York

In the New York State Learning Standards, this is unit 2 of 20 in 7th grade Math, after Add & Subtract Integers and before Fractions, Decimals & Percents.

Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.

Source: New York State Education Department (NYSED)

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    Apples cost $3.20 per kilogram. How much do 3.3 kg of apples cost, in dollars?

    answer box

  2. Question 2

    What is 3 ÷ 0.3?

    3 ÷ 0.3 = ?

    answer box

  3. Question 3

    What is 7.9 − 1.24?

    7.9 − 1.24 = ?

    answer box

  4. Question 4

    What is 9.9 × 0.8?

    9.9 × 0.8 = ?

    • 79.2
    • 7.92
    • 0.0792
    • 0.792

  5. Question 5

    Put these decimals in order from least to greatest.

    • 0.038
    • 0.803
    • 0.8
    • 0.839
    • 0.38

  6. Question 6

    Use the order of operations: what is 5.1 + 4.1 × 5?

    5.1 + 4.1 × 5

    • 29.6
    • 25.7
    • 46
    • 25.6

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