Counting Examples in Math

Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of Counting.

This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Math.

Concept Recap

Determining the total number of objects in a set by assigning exactly one number to each object in sequence, where the last number spoken equals the total count (the cardinality of the set).

Like pointing to each toy and saying '1, 2, 3...' to know how many toys you have.

Read the full concept explanation โ†’

How to Use These Examples

  • Read the first worked example with the solution open so the structure is clear.
  • Try the practice problems before revealing each solution.
  • Use the related concepts and background knowledge badges if you feel stuck.

What to Focus On

Core idea: Counting tags each object with the next counting word and the final word names how many there are.

Common stuck point: The procedure for counting is the easy part; the trap is counting an object twice or skipping one. Asking "Did I touch each object exactly once and is the last number I said the total?" first is what keeps a correct-looking calculation from being attached to the wrong concept.

Sense of Study hint: Ask: Did I touch each object exactly once and is the last number I said the total?

Worked Examples

Example 1

easy
A student counts the dots on a domino. The left side has 3 dots and the right side has 4 dots. How many dots are there in total?

Answer

77

First step

1
Count the left side: 1, 2, 3 โ€” there are 3 dots.

Full solution

  1. 2
    Count the right side: 1, 2, 3, 4 โ€” there are 4 dots.
  2. 3
    Count all dots together starting from 1: 1, 2, 3, 4, 5, 6, 7 โ€” the total is 7 dots.
Counting assigns one number to each object in sequence. The last number spoken is the total (cardinality). Counting on from the first group (starting at 3 and continuing 4, 5, 6, 7) is a key efficiency strategy.

Example 2

medium
How many letters are in the word MATHEMATICS? Count carefully โ€” some letters repeat.

Example 3

easy
๐Ÿ“๐Ÿ“. How many strawberries?

Example 4

easy
Which numeral is this: 33?

Example 5

medium
๐Ÿฆ‹. How many butterflies?

Example 6

easy
There are 9 ducks in the pond. Count them. How many ducks?

Example 7

easy
Count backward from 10 to 1. How many numbers do you say?

Example 8

medium
๐ŸŽ๐ŸŽ๐ŸŽ๐ŸŽ๐ŸŽ๐ŸŽ๐ŸŽ๐ŸŽ. How many apples?

Example 9

easy
Skip-count by 5s from 5 to 30. List the numbers.

Example 10

easy
What number comes just after 99?

Example 11

hard
Skip-count by 5s from 5 to 50. How many numbers do you say?

Example 12

easy
Skip-count by 10s from 250: 250,260,270,__,__250, 260, 270, \_\_, \_\_.

Example 13

easy
A jar holds 600 beads. The next jar has 100 more. How many beads are in the next jar?

Example 14

hard
Start at 480 and skip-count by 5s. What is the 4th number you say after 480?

Practice Problems

Try these problems on your own first, then open the solution to compare your method.

Example 1

easy
Skip-count by 5s starting at 5 and list the first six multiples.

Example 2

medium
A bag contains red, blue, and green marbles. There are 4 red, 3 blue, and 5 green marbles. Without counting the whole bag at once, use grouping to find the total.

Example 3

easy
How many objects: โˆ™โˆ™โˆ™โˆ™โˆ™\bullet \bullet \bullet \bullet \bullet?

Example 4

easy
Count by twos: 2,4,6,__,__2, 4, 6, \_\_, \_\_. Fill in the next two.

Example 5

easy
What number comes just before 2020?

Example 6

easy
Count backward from 1010 to 66. How many numbers do you say?

Example 7

easy
Count by tens: 10,20,30,__10, 20, 30, \_\_. What's next?

Example 8

easy
How many fingers on two hands?

Example 9

easy
Count by fives to 2525: 5,10,15,__,__5, 10, 15, \_\_, \_\_.

Example 10

easy
If there are 33 red balls and 44 blue balls, how many balls total?

Example 11

medium
How many whole numbers are there from 55 to 1212 inclusive?

Example 12

medium
How many even numbers are between 11 and 2020 inclusive?

Example 13

medium
A staircase has 1515 steps. If you're on step 44, how many more to reach the top?

Example 14

medium
Count by threes from 33 to 3030. How many numbers?

Example 15

medium
A pattern repeats every 44 beats: clap, snap, stomp, rest. On beat 1010, which action?

Example 16

medium
There are 77 houses on a street. How many gaps between adjacent houses?

Example 17

medium
Counting numbers 11 to 100100: how many contain the digit 77 in the ones place?

Example 18

medium
How many numbers from 11 to 5050 are multiples of 55?

Example 19

medium
A clock chimes once at 1:00, twice at 2:00, etc. How many chimes from 1:00 to 6:00?

Example 20

challenge
How many numbers from 11 to 100100 are divisible by 22 or 33?

Example 21

challenge
Pages numbered 11 to 100100. How many digits are printed in total?

Example 22

challenge
In a single-elimination tournament with 1616 players, how many games are played to determine a winner?

Example 23

easy
๐Ÿ๐Ÿ๐Ÿ. How many bees?

Example 24

easy
Which numeral is this: 44?

Example 25

easy
Hold up 5 fingers. Count them.

Example 26

medium
๐Ÿ ๐Ÿ ๐Ÿ ๐Ÿ . How many fish?

Example 27

hard
๐Ÿฑ๐Ÿฑ๐Ÿฑ๐Ÿฑ๐Ÿฑ. How many cats?

Example 28

easy
Count to 10 out loud. What number comes after 7?

Example 29

easy
Count backward from 10: 10,9,8,__10, 9, 8, \_\_. What comes next?

Example 30

easy
What number comes just before 6?

Example 31

medium
Fill in the blanks: 1,2,3,__,5,6,__,8,9,101, 2, 3, \_\_, 5, 6, \_\_, 8, 9, 10.

Example 32

medium
Count backward from 10: 10,9,8,7,__,510, 9, 8, 7, \_\_, 5. What is missing?

Example 33

easy
Fill in the blanks: 47,48,__,__,5147, 48, \_\_, \_\_, 51.

Example 34

easy
Skip-count by 2s: 2,4,6,8,__,__2, 4, 6, 8, \_\_, \_\_.

Example 35

easy
Skip-count by 10s: 10,20,30,40,__10, 20, 30, 40, \_\_.

Example 36

medium
Skip-count by 2s starting at 14: 14,16,18,__,__14, 16, 18, \_\_, \_\_.

Example 37

medium
Sam counts his pennies by 5s: 5,10,15,20,25,30,355, 10, 15, 20, 25, 30, 35. How many pennies in all?

Example 38

easy
Skip-count by 100s: 100,200,300,__,__100, 200, 300, \_\_, \_\_.

Example 39

easy
Fill in: 497,498,499,__,501497, 498, 499, \_\_, 501.

Example 40

easy
Skip-count by 5s starting at 425: 425,430,435,__425, 430, 435, \_\_.

Example 41

medium
Skip-count by 100s starting at 350: 350,450,550,__,__350, 450, 550, \_\_, \_\_.

Example 42

medium
Fill in: 789,790,__,__,793789, 790, \_\_, \_\_, 793.