Help D.C. with number sentences and ten frames, then learn about groups of up to 20. Join Mrs. Gray for a Mystery Math Mistake with D.C. He needs help figuring out his number sentences to match ten ...

When you count to 20, you start at 1 (or zero) and count on until you reach 20. Each number is one more than the last. When you count back from 20, you start at 20 and count back until you reach 1 (or ...

In Obduction, the Villeins use a base 4 number system — and you'll have to use it to solve puzzles. To understand it, you have to think about our own numbers for a minute. We use base 10. This means ...

Learn about counting the numbers 1, 2, 3, 4 and 5.. Counting to 10 Learn about counting the numbers, 6, 7, 8, 9 and 10 using objects. One more and less within 10 ...

The idea of an animal that can count or do math might sound like something out of a viral news story or TikTok video. But a sense of quantity, sometimes called "numerosity," appears across a ...