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Number Trail Grade 4 / Week 10 / Wednesday
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Week 10 · Tenths and hundredths

Wednesday

Compare decimals
// Decimals show parts of a whole
⏱ about 15 min

Wednesday: Compare decimals

Lizzy the Lizard and Bennie the Bear measure two vines by the garden fence.

The ivy vine is 0.5 meter long. The bean vine is 0.45 meter long.

"The bean vine is longer," says Lizzy. "Forty-five is bigger than five!"

Bennie smiles kindly. "Let us look closer with hundred grids."

He shades both grids. The ivy grid has five full columns.

The bean grid has only four full columns and five more squares.

Lizzy taps her notebook. "Oh! 0.5 is the same as 0.50. So the ivy vine is longer."

Learn it: compare place by place

A hundred grid with 50 squares shaded, five full columns
A hundred grid with 45 squares shaded

0.5 = 0.50, which is 50 hundredths. 0.45 is 45 hundredths.

50 hundredths is more than 45 hundredths, so 0.5 > 0.45.

Another way: compare the tenths first. 5 tenths is more than 4 tenths.

Only look at the hundredths when the tenths are the same.

Compare decimals only when they are parts of the same whole.

Half of a big branch can be longer than half of a small twig.

WHICH SIGN GOES BETWEEN THEM?
  • Read the question.
  • Tap your answer.
0.5 ? 0.45
0.3 ? 0.30
0.09 ? 0.1
1.2 ? 0.98
0.67 ? 0.76
WHICH IS GREATER?
  • Read the question.
  • Tap your answer.
Which is greater, 0.6 or 0.06?
Which is greater, 0.34 or 0.4?
Which is greater, 2.1 or 1.99?
Which is greater, 0.7 or 0.69?
DECIMALS ON A NUMBER LINE
  • Read the question.
  • Tap your answer.
A number line from 0.60 to 0.70, with a dot at 0.62What decimal is at the dot?
A number line from 0.0 to 1.0, with a dot at 0.35The dot is halfway between two tenths. What decimal is it?
A number line from 0.0 to 1.0Which decimal is closer to 1?
ORDER THE DECIMALS
  • Compare the tenths first.
  • Tap the decimals from least to greatest.
11st
22nd
33rd
44th
55th
SentenceTrue or false?
0.5 > 0.45?
0.09 > 0.1?
0.3 = 0.30?
1.2 < 0.98?
We compare decimals only when they are parts of the same whole.?
WHY THIS EXERCISE0.09 has 0 tenths, so it is less than 0.1. And 1.2 has a whole one, so it is greater than 0.98.
Try it
Write these on small cards: 0.4, 0.04, 0.44, 0.14 and 0.41.
Put the cards in order from least to greatest.
Check by thinking of each one as hundredths.
Read the order out loud to someone at home.
Draw two hundred grids. Shade 0.3 on one and 0.25 on the other. Circle the greater one.

Nice comparing! Tomorrow Chris tells a story about a slow snail.

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