Counting Sets of Dimes (Counting by 10s) - First Grade Mathematics

If counting pennies is like walking, counting dimes is like zooming on a skateboard! Because each dime is worth ten cents, counting a set of dimes allows you to use your skip counting by 10s superpower. Instead of counting individual cents, your running total jumps by ten with every coin you touch. In this chapter, you will master counting collections of dimes up to 100 cents, write their values using the cent symbol, and discover how ten dimes make one whole dollar.

Counting by Tens with Dimes

Every time you place another dime on the table, add 10¢ to your running total.

Counting a Set of 5 Dimes:
  (10c)      (10c)      (10c)      (10c)      (10c)
    |          |          |          |          |
   10¢        20¢        30¢        40¢        50¢

Total Value: 50¢ (Fifty Cents!)

The Touch-and-Count Rhythm

Touch each dime firmly and chant with rhythm: "10¢, 20¢, 30¢, 40¢, 50¢, 60¢, 70¢, 80¢, 90¢, 100¢!" Counting dimes is rapid, accurate, and fun.

The Connection to Base-Ten Rods

Look at how dimes compare to the rods of ten you used in Unit 2:

Base-Ten Rods vs. Dimes:
1 Rod of Ten Cubes  =  10 Units  =  Value of 10
1 Dime Coin         =  10 Cents  =  Value of 10¢

3 Rods of Ten  =  30 Cubes
3 Dimes        =  30 Cents (30¢)

Pure Tens

A set of dimes has zero loose pennies. That is why every total made of pure dimes always ends with a 0: 10¢, 20¢, 30¢, 40¢, etc.!

Ten Dimes Make One Dollar

When you collect 10 dimes, you reach a major milestone:

The 10-Dime Dollar:
10 Dimes = 100 Cents = $1.00 (One Whole Dollar!)

Practice Exercises

Exercise 1: Count this collection of dimes by 10s and state the total value: (10¢) (10¢) (10¢) (10¢).

Exercise 2: How many dimes do you need to buy a juice box that costs 70¢?

Exercise 3: You have 9 dimes in your coin purse. How many cents do you have in total?

Exercise 4: Explain why the total value of any set of only dimes will always end in the digit 0.

Solutions and Explanations

Solution to Exercise 1: Counting by 10s: 10¢, 20¢, 30¢, 40¢. The total value is 40¢.

Solution to Exercise 2: You need 7 dimes. Counting 7 dimes by 10s gives 70¢ (10, 20, 30, 40, 50, 60, 70).

Solution to Exercise 3: You have 90¢ (9 dimes x 10¢ = 90¢).

Solution to Exercise 4: The total value always ends in 0 because each dime is worth 10 cents, which has 1 ten and 0 ones. When you add multiples of 10 together, there are zero loose ones, so the ones digit remains 0.