Bridges in Mathematics Grade 4, Unit 4: Addition Subtraction & Measurement
In this unit, your child works with whole numbers up to a million: reading, comparing, and rounding them; and adding and subtracting them with the column method. They also convert measurements, like feet to inches, and solve story problems about distance, time, and money. It follows the fraction and decimal work, and leads into geometry and more measuring.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 4?
- Explaining why each place is worth ten times the place to its right, so 700 is ten times 70. Learn more: Why each place is worth ten times the next
- Reading and writing numbers up to a million in digits, words, and expanded form, and comparing them with >, =, and <. Learn more about reading and writing numbers up to a million: Reading and writing numbers up to a million · Learn more about comparing numbers up to a million
- Rounding large numbers to any place, like 36,718 to 37,000, to make quick estimates. Learn more: Rounding big numbers to any place
- Adding and subtracting large numbers in columns, regrouping across places and across zeros. Learn more about adding numbers up to a million: Adding numbers up to a million · Learn more about subtracting numbers up to a million
- Converting a larger unit to a smaller one, like 4 feet to 48 inches or 2 kilograms to 2,000 grams. Learn more: Converting feet to inches and kilograms to grams
- Solving story problems about distance, time, liquid volume, weight, and money, often with a number line. Learn more: Story problems about distance, time, and money
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
Compare 40 thousands and 4 ten thousands. Which is true?
- 4 ten thousands is more
- They are equal
- 40 thousands is more
How you can help
- Read big numbers you see on a walk or ride, like a town's population on a sign. Ask your child to read it aloud, round it to the nearest thousand, and say which place told them.
- Add up a grocery receipt together, rounding to whole dollars. Have your child write the amounts in a column, add them, and compare the total with the receipt.
- Measure family members with a tape measure. If someone is 5 feet tall, ask your child how many inches that is, then check the answer of 60 with the tape.
Where kids can get stuck
- Subtracting the smaller digit from the larger in each column, so 52 − 38 comes out as 26 instead of 14.
- Judging by the first digit alone, so 9,850 seems greater than 12,400.
- Dividing instead of multiplying when changing feet to inches, so 4 feet comes out as fewer than 4 inches.
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
- The value a digit has because of its place in a number.
- digit
- Any of the symbols 0 through 9 used to write numbers.
- expanded form
- A number written as the sum of each digit's value, like 3,000 + 400 + 5.
- round
- To change a number to a nearby, easier number, like 6,812 to 7,000.
- regroup
- To trade 10 of one place for 1 of the next, like 10 tens for 1 hundred.
- algorithm
- A step-by-step method for solving a problem, like adding numbers in columns.
- convert
- To change a measurement into a different unit, like 3 feet into 36 inches.
- elapsed time
- How much time passes between the start and the end of an event.
Want to help your child master big numbers and measurement?
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 Bridges in Mathematics Grade 4 Unit 4 cover?
Bridges in Mathematics Grade 4 Unit 4 covers these math standards. Each one links to what it means, sample questions, and teaching strategies.
- 4.NBT.A.1: Know that each place is worth 10 times the place to its right.
- 4.NBT.A.2: Read, write, and compare numbers up to a million.
- 4.NBT.A.3: Round large numbers to any place, like 6,812 to 7,000.
- 4.NBT.B.4: Fluently add and subtract numbers up to a million.
- 4.MD.A.1: Change larger units into smaller ones, like 4 feet = 48 inches.
- 4.MD.A.2: Solve word problems about distance, time, liquids, weight, and money.
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.