Eureka Math² Grade 1, Module 5: Place Value Concepts to Compare and Add Numbers to 100
In this unit, first graders use place value, what each digit in a number is worth, to compare and add numbers to 100. They count to 120, see two-digit numbers as tens and ones, find 10 more and 10 less, and add and subtract tens. After measuring lengths in the last unit, this is the year's big number work, and next they study shapes, time, and equal shares.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Module 5?
- Counting by ones and tens to 120 from any number, and reading and writing numbers like 99, 100, and 101. Learn more: Counting, reading, and writing numbers to 120
- Reading two-digit numbers as tens and ones, so 68 is 6 tens and 8 ones, and 90 is 9 tens. Learn more: Tens and ones in two-digit numbers
- Comparing numbers to 100 by their tens and ones and writing the result with >, <, or =. Learn more: Comparing two-digit numbers with >, =, and <
- Adding a two-digit number and a one-digit number, or a multiple of ten, by adding like units and making a new ten. Learn more: Adding two-digit numbers within 100
- Telling 10 more or 10 less than any number to 100 without counting, such as 57 and 47. Learn more: 10 more or 10 less in your head
- Subtracting multiples of ten, like 70 - 40, and connecting it to counting back by tens. Learn more: Subtracting tens, like 70 - 30
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
Count by tens: 10, 20, 30, 40, __. What number comes next?
- 51
- 50
- 60
How you can help
- Count out a big pile of pasta or cereal into cups of ten, then write the number. Ask how many tens and ones there are, then remove a cup to find 10 less.
- Compare numbers on house doors or price tags on a walk or at the store, and ask which is greater and how they knew.
- Ask an adding question at snack time, like "You have 56 stickers and get 8 more. How many now?" Let your child explain how they made a new ten.
Where kids can get stuck
- Counting by ones ten times to find 10 more than 56, and miscounting along the way.
- Mixing up > and <, writing 46 > 64 when 64 is greater.
- Lining the 8 up under the 5 in 56 + 8 and adding it to the tens.
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
- place value
- What a digit is worth because of its spot, like the 4 in 42 meaning 40.
- digit
- One of the symbols 0 to 9 used to write numbers.
- tens
- Groups of ten. In 34, there are 3 tens.
- ones
- Single things not in a group of ten. In 34, there are 4 ones.
- greater than
- The symbol > means the first number is bigger, like 9 > 4.
- less than
- The symbol < means the first number is smaller, like 4 < 9.
- 10 more
- The number you get by adding one ten, like 46 to 56.
- 10 less
- The number you get by taking away one ten, like 46 to 36.
- multiple of 10
- A number you say when counting by tens, like 30 or 70.
Ready to build your child’s confidence with place value to 100?
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.
Join the club
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 Eureka Math² Grade 1 Module 5 cover?
Eureka Math² Grade 1 Module 5 covers these math standards. Each one links to what it means, sample questions, and teaching strategies.
- 1.NBT.A.1: Count to 120, starting at any number.
- 1.NBT.B.2: Understand that the two digits of a two-digit number represent amounts of tens and ones.
- 1.NBT.B.3: Compare two two-digit numbers.
- 1.NBT.C.4: Add within 100.
- 1.NBT.C.5: Given a two-digit number, mentally find 10 more or 10 less.
- 1.NBT.C.6: Subtract multiples of 10 in the range 10-90.
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.