# Teaching 4.NF.C.7 – Compare Two Decimals to Hundredths by Reasoning about their Size

## Number & Operations – Fractions – 4th Grade

**Understand decimal notation for fractions, and compare decimal fractions.**

CCSS.Math.Content.4.NF.C.7

Compare two decimals to hundredths by reasoning about their size. Recognize that comparisons are valid only when the two decimals refer to the same whole. Record the results of comparisons with the symbols >, =, or <, and justify the conclusions, e.g., by using a visual model.

**Teacher Notes**

Decimal comparisons, like fraction comparisons, are only valid if the whole is the same size. There are multiple ways to compare decimals (place value positions, visual models, estimation) just as there are multiple ways to compare whole numbers.

Students may think that a decimal is the decimal point rather than a number. Students need to understand that the decimal point is a symbol that indicates the location of the ones place and all other subsequent place values in the decimal system. The decimal point separates the whole number amount from a number that is less than one.

**Student Knowledge Goals**

I know comparisons are valid when the two decimals refer to the same whole.

I can justify conclusions about the comparison of decimals using visual models and other methods.

I can relate a decimal to a whole number.

I can use what I know about fractions to help me compare decimals.

**Vocabulary**

comparison symbols (<, >, =)

decimals

hundredths

tenths

visual models for decimals (grid paper, number line, base ten blocks etc.)

whole

**Lessons**

Engage NY Module 6 C-9 – Use the place value chart and metric measurement to compare decimals and answer comparison questions.

Engage NY Module 6 C-10 – Use area models and the number line to compare decimal numbers, and record comparisons using <, >, and =.

Engage NY Module 6 C-11 – Compare and order mixed numbers in various forms.

Engage NY Module 6 D-12 – Apply understanding of fraction equivalence to add tenths and hundredths.

Engage NY Module 6 D-13 – Add decimal numbers by converting to fraction form.

**Student Video Lessons**

Learn Zillion – Compare two decimals to hundredths by reasoning about their size

Virtual Nerd – Comparing decimals

Study Jams – Comparing decimals on a number line

**Online Problems and Assessments**

Khan Academy – Questions and Video Lessons

Compare money amounts

Compare decimals on number lines

Compare decimal numbers

Put decimal numbers in order

Put tricky decimals in order

Compare fractions and decimals on number lines

**Online Games**

Comparing Decimals

**Printables**

Comparing Decimals

Assessment Task 1

Assessment Task 2

Assessment Task 3

Assessment Task 4

Assessment Task 5

Assessment Task 6

Assessment Task 7

Performance Task 1