Decimals and Place Value — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
On a number line, 0.9 comes right after 0.10.
Corrected: On a number line, 0.9 comes right before 1.0 and is much greater than 0.10.
The corrected sentence is: "On a number line, 0.9 comes right before 1.0 and is much greater than 0.10." The error was confused digit count with value: the original sentence "On a number line, 0.9 comes right after 0.10." needed to be fixed.
2. Fix the sentence:
The decimal 0.30 is less than 0.3 because it has a zero at the end.
Corrected: The decimal 0.30 is equal to 0.3 because a trailing zero does not change the value.
The corrected sentence is: "The decimal 0.30 is equal to 0.3 because a trailing zero does not change the value." The error was trailing zero misconception: the original sentence "The decimal 0.30 is less than 0.3 because it has a zero at the end." needed to be fixed.
3. Fix the sentence:
In the number 7.52, the digit 5 is in the hundredths place.
Corrected: In the number 7.52, the digit 5 is in the tenths place.
The corrected sentence is: "In the number 7.52, the digit 5 is in the tenths place." The error was wrong place value name: the original sentence "In the number 7.52, the digit 5 is in the hundredths place." needed to be fixed.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. On a number line from 0 to 1, the point 0.5 is exactly in the middle.
"Middle" is correct because 0.5 equals one half, and half of the distance from 0 to 1 lands right at the center of the number line.
2. Use >, <, or = : 0.72 > 0.7.
The answer is ">" because 0.7 equals 0.70, and 72 hundredths is greater than 70 hundredths.
3. The number line shows 10 equal jumps from 0 to 1. Each jump is 1 tenth(s).
Each jump is 1 tenth because splitting the distance from 0 to 1 into 10 equal parts means each part is 110, or one tenth.
4. The decimal 0.85 is between 0.8 and 0.9 on a number line.
0.9 is correct because 0.85 has 8 tenths plus 5 hundredths, placing it halfway between the 0.8 mark and the 0.9 mark on a number line.
Part C: Short Answer
Answer each question in one or two complete sentences.
1. Which is greater, 0.6 or 0.58? Explain how you know.
Sample answer: 0.6 is greater because 0.6 equals 0.60, and 60 hundredths is more than 58 hundredths.
A good answer includes: 0.6 is greater because 0.6 equals 0.60, and 60 hundredths is more than 58 hundredths.
2. Why is it helpful to use a number line when comparing decimals?
Sample answer: A number line shows the position of each decimal so you can see which one is farther to the right, meaning it is the greater number.
A good answer includes: A number line shows the position of each decimal so you can see which one is farther to the right, meaning it is the greater number.