Two happy children standing beside leafy bean plants in a garden

The Great Plant Contest

Maya's bean plant is 0.5 meters tall. Leo's is 0.45 meters tall. Leo says 45 beats 5, so he wins. Is he right? Let's find out!

4th Grade Math

Step 1: Read the Tenths

Maya's height is the decimal 0.5. The first digit after the point counts tenths. The bar shows the whole meter cut into 10 equal parts. How many tenths does 0.5 name?

The 5 sits in the tenths place, so 0.5 means 5 tenths. The bar shows 5 of 10 equal parts shaded.

Step 2: Make the Places Match

Leo's height, 0.45, uses hundredths. To compare fairly, write Maya's 0.5 with hundredths too. Which decimal fills the blank?

0.5 = ?

0.5 and 0.50 are equal. A zero at the end does not change the value. 5 tenths = 50 hundredths.

Let's Remember

How to Compare Decimals

          Step 1: Line up the decimal points.

          Step 2: Compare the tenths first.

          Step 3: If tenths tie, compare the hundredths.

One more rule: only compare decimals that describe the same whole. Half of a giant pumpkin is not the same as half of a grape!

Step 3: Compare!

0.40

0.41

0.42

0.43

0.44

0.45

0.46

0.47

0.48

0.49

0.50

Find Leo's 0.45 in orange and Maya's 0.50 in blue. Which symbol is true?

0.50 ? 0.45

0.50 sits to the right of 0.45, so 0.50 > 0.45. Fifty hundredths beats forty-five hundredths. Maya's plant wins!

Watch Out!

The Longer-Is-Bigger Trap

          Leo thought 0.45 > 0.5 because 45 looks bigger than 5.

          But decimals are not whole numbers!

          0.5 = 0.50, and 50 hundredths > 45 hundredths.

Always justify your answer with a model, like a number line. Compare place by place, starting with the tenths.

Solve It!

Which symbol makes this true?

0.7 ? 0.68

0.7 = 0.70. Compare hundredths: 70 > 68, so 0.7 > 0.68.

Word Problem

At field day, Nia jumped 0.62 meters high. Amir jumped 0.6 meters high. Who jumped higher?

0.6 = 0.60. The tenths tie at 6, so check hundredths: 62 > 60. Nia jumped higher.

What Goes in the Blank?

Determine which decimal makes this true.

0.34 < ?

0.43 has 4 tenths, which beats 3 tenths. 0.29 is less, and 0.34 is equal, not greater.

Tricky Twins

Which symbol makes this true?

0.80 ? 0.8

8 tenths equals 80 hundredths. The extra zero does not add any value, so 0.80 = 0.8.

Same Whole?

Ben ate 0.5 of a small pizza. Lena ate 0.4 of a large pizza. Ben says he ate more pizza. Is his comparison valid?

Comparisons only work when both decimals refer to the same whole. 0.4 of a large pizza could be more food than 0.5 of a small one.

Challenge Round!

Three swimmers swam these fractions of a lap: 0.9, 0.19, and 0.91. Which decimal is the greatest?

Rewrite 0.9 as 0.90. Now compare hundredths: 91 > 90 > 19. So 0.91 is greatest, and 0.19 is least.

Race times are measured in hundredths of a second. Why does the runner with the smaller decimal win?

Great Work!

0/8

correct

decimal tenths hundredths justify determine