Go Math! Grade 4, Chapter 9: Relate Fractions and Decimals
In this unit, your child links fractions to decimals. They write tenths and hundredths as decimals, rename tenths as hundredths to add them, and compare decimals to the hundredths. Money, like dimes and pennies, makes the ideas concrete. It follows the fraction units and leads into two-dimensional shapes.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Chapter 9?
- Adding tenths and hundredths, like 6/10 + 25/100, by first renaming 6/10 as 60/100. Learn more: Adding tenths and hundredths together
- Writing amounts like 62 cents as 62/100 of a dollar and as $0.62, and reading decimals in words. Learn more: Writing fractions as decimals, like 0.62
- Comparing decimals like 0.09 and 0.1 by renaming them in hundredths, 9 and 10, and using >, =, or <. Learn more: Comparing decimals like 0.09 and 0.1
Sample questions to try together
These are real questions from our practice. Tap the speaker to hear one read aloud, or the light bulb for a hint, and talk about the answer together.
Question 1 of 3
How many hundredths make the same amount as 1/10?
- 1
- 10
- 100
How you can help
- Put out 6 dimes and 5 pennies. Ask your child what fraction of a dollar that is, and to write it as 65/100 and as $0.65.
- Look at rainfall or race times in the news, like 0.08 inches of rain. Ask your child to say it as a fraction and decide whether it is more or less than one tenth.
- Pick two items under a dollar at the store, like $0.45 and $0.50. Ask your child which costs more, and to explain using dimes and pennies.
Where kids can get stuck
- Writing 4/100 as 0.4 instead of 0.04, skipping the zero in the tenths place.
- Thinking 0.09 is greater than 0.1 because 9 is greater than 1.
- Adding 6/10 + 25/100 as 31/110, without renaming the tenths first.
Practice makes perfect
Bobby's Math Club has practice problems that adapt to your child’s level, each with a detailed explanation and an easy-to-follow video, so your child can build confidence in these skills one step at a time.
Words your child will hear
- decimal
- A number written with a decimal point, like 0.62, to show parts of a whole.
- decimal point
- The dot that separates the whole number from the tenths and hundredths.
- tenth
- One of 10 equal parts of a whole, written 1/10 or 0.1.
- hundredth
- One of 100 equal parts of a whole, written 1/100 or 0.01.
- tenths place
- The first place to the right of the decimal point.
- hundredths place
- The second place to the right of the decimal point.
Want to help your child master decimals and money?
In Bobby's Math Club, your child practices these skills at just the right level, with a hint when they need one, a clear explanation after every question, and kid-friendly videos. Unlimited practice is free.
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Written by Robert “Bobby” Barnett
Bobby is an award-winning math teacher, the author of Meet Every Learner’s Needs, and the father of two elementary-school math learners. He uses Bobby’s Math Club with his own kids a few times every week. Learn more or contact Bobby.
Which math standards does Go Math! Grade 4 Chapter 9 cover?
Go Math! Grade 4 Chapter 9 covers these math standards. Each one links to what it means, sample questions, and teaching strategies.
For teachers: Unit names and order vary between editions and districts, so your school’s own materials have the exact sequence. Learn how Bobby's Math Club can help your students grow.