Math Core

Lesson 3.1 · Counting to 100

Counting to 20

You can count to 10. Now let's count past 10, all the way to 20! That's how many fingers and toes you have.

Counting words after 10

After ten, the counting keeps going.

1112131415
eleventwelvethirteenfourteenfifteen
1617181920
sixteenseventeeneighteennineteentwenty

Eleven and twelve are new words. The rest sound like the numbers you know: sixteen, seventeen, eighteen, nineteen.

Rows of 10

Big groups are easier to count in rows. Put 10 in the top row. A full row is ten. Then keep counting the next row: eleven, twelve, …

Don't start over

When a row of 10 is full, keep going. The next number is eleven, not "one."

Worked example: Count the ducks

How many ducks?

🦆 🦆 🦆 🦆 🦆 🦆 🦆 🦆 🦆 🦆

🦆 🦆

The top row is full, so it has 10. Keep going on the bottom row: eleven, twelve. There are 12 ducks.

Worked example: Count the apples

How many apples?

🍎 🍎 🍎 🍎 🍎 🍎 🍎 🍎 🍎 🍎

🍎 🍎 🍎 🍎 🍎 🍎

Top row: 10. Bottom row: eleven, twelve, thirteen, fourteen, fifteen, sixteen. There are 16 apples.

Worked example: Two full rows

How many stars?

⭐ ⭐ ⭐ ⭐ ⭐ ⭐ ⭐ ⭐ ⭐ ⭐

⭐ ⭐ ⭐ ⭐ ⭐ ⭐ ⭐ ⭐ ⭐ ⭐

Top row: 10. Bottom row: eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen, twenty. There are 20 stars.

Common mistake

Watch out for fifteen. It is not "five-teen." And thirteen is not "three-teen."

Practice

Practice 1

How many fish?

🐟 🐟 🐟 🐟 🐟 🐟 🐟 🐟 🐟 🐟

🐟

Type a number.

Practice 2

How many leaves?

🍃 🍃 🍃 🍃 🍃 🍃 🍃 🍃 🍃 🍃

🍃 🍃 🍃 🍃

Type a number.

Practice 3

How many balls?

⚽ ⚽ ⚽ ⚽ ⚽ ⚽ ⚽ ⚽ ⚽ ⚽

⚽ ⚽ ⚽ ⚽ ⚽ ⚽ ⚽

Type a number.

Practice 4

What number comes right after 12?

Practice 5

What number comes right after 18?

Type a number.

Practice 6

What number is missing?

13, 14, ___, 16, 17

Type a number.

Practice 7

Which group has 18 hearts?