Bridges in Mathematics Kindergarten, Unit 8: Computing & Measuring
In this unit, the year's last, your child pulls kindergarten math together. Kindergartners count to 100 by ones and by tens, get quicker at adding and subtracting within 5, and compare lengths by lining objects up side by side. Coming after the weight and capacity unit, it rounds out measuring with length and sends your child into first grade ready to count, compare, and compute.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 8?
- Counting to 100 by ones and by tens, and moving smoothly past tricky spots like 29 to 30 and 89 to 90. Learn more about counting to 100 by ones: Counting to 100 by ones · Learn more about counting to 100 by tens
- Adding and subtracting within 5 quickly, such as 3 + 2 = 5 and 4 - 1 = 3, without counting on fingers every time. Learn more about adding fluently within 5: Adding fluently within 5 · Learn more about subtracting fluently within 5
- Describing objects by their length, how long they are, and their height, how tall they are, as well as by weight. Learn more: Describing how long or heavy things are
- Comparing two objects by lining up their ends side by side to see which is longer or shorter. Learn more: Comparing which is longer, taller, or heavier
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
What comes next? 10, 20, 30, 40, __
- 60
- 50
- 41
How you can help
- Count to 100 together on a long walk or ride, taking turns with each group of ten, so your child says 21 to 30 and you say 31 to 40.
- Lay two spoons, shoes, or scarves side by side on the floor with their ends lined up, and ask your child which is longer and how they can tell.
- Play a quick fact game while waiting in line, asking questions like 'What is 2 and 3?' or 'What is 4 take away 1?' and cheering careful answers.
Where kids can get stuck
- Getting stuck at the end of a group of ten, saying 'thirty-nine, thirty-ten' instead of forty.
- Comparing two pencils without lining up their ends, so the one that sticks out further looks longer.
- Counting every small fact from 1 on their fingers, so answers within 5 come out right but slowly.
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
- count by tens
- Saying 10, 20, 30, and so on, up to 100.
- hundred
- The number 100, which is the same as ten tens.
- fact
- A small adding or subtracting problem kids learn to just know, like 2 + 2 = 4.
- sum
- The answer when you add; in 2 + 3 = 5, the sum is 5.
- difference
- The answer when you subtract; in 5 - 1 = 4, the difference is 4.
- length
- How long something is from one end to the other.
- longer
- Stretching further from end to end than something else.
- shorter
- Not as long or not as tall as something else.
Want to help your child master counting, adding, and measuring?
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 Kindergarten Unit 8 cover?
Bridges in Mathematics Kindergarten Unit 8 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.