Math Background

Time Intervals and Money Amounts: Overview

Students are easily motivated to study the topics in this chapter because they use them every day. You can reinforce these skills informally throughout the year.

At the beginning of the chapter, students are introduced to coins and bills. They start with dollars, dimes, and pennies, then move on to half-dollars, quarters, and nickels.

Make sure your students understand how to write money amounts using a dollar sign and decimal point. The numbers to the left of the decimal point are dollar amounts. If the amount of money is less than one dollar, a zero is used as a placeholder for dollars.

thirty-four cents

The numbers to the right of the decimal point are cents. Cents always have two digits, even when the number of cents is less than 10.

One dollar and eight cents

Give students ample practice counting by fives, tens, and twenty-fives. Show them that it is easier to count bills and coins from greater to lesser values than from lesser to greater values. (See the answer to the second question in “When Students Ask.”) Mastery of these skills will make learning to count money easy.

One dollar, two quarters, two dimes, one nickel, and one penny

Keep a supply of play coins and bills on hand so students can challenge each other to find different combinations that have the same, or equivalent, value.

fifteen cents equals: one dime and one nickel, three nickels, one dime and five pennies, or two nickels and five pennies

Students can also use play money to practice making change at a General Store in the classroom. (See “Tips and Tricks.”) They will discover that to count change easily, they should go from the lesser to the greater value.

change for thirty-nine cents from a dollar is sixty-one cents - two quarters, one dime, and one penny

Encourage students to create their own games and activities that reinforce the concepts they have learned about money. This can be a fun and valuable experience for them.

The chapter also focuses on telling time. If commercial educational clocks are not available, make your own clocks from Learning Tool 21. Students will use them throughout the remainder of the chapter.

Don't move students too quickly through time-telling concepts. Make sure they master the basic skills first, such as knowing the difference between the minute hand and hour hand, recognizing the minute and hour marks around the clock, and telling time to the hour, half-hour, and quarter-hour. Once students have acquired these skills, they will be ready to tell time to five minutes and to the minute.

Be sure to focus students' attention on minutes before and after the hour. This is where they will use their skills in counting on and counting back. They count on from the 12 to tell time after the hour and count back from the 12 to tell time before the hour.

two clocks with the same time, one caption reading forty minutes after five, the other caption reading twenty minutes before six

Encourage students to observe both hands on the clock when they tell time. Notice that the hour hand on the clock above is between the 5 and 6. When the time is at the hour, the hour hand points straight to a number.

A good foundation in telling time will help students make an easy transition to finding elapsed time. Students will explore how to find the amount of time that has passed since a given time, and how to find the time it will be when a given amount of time has passed.

  • From 5:15 to 5:55, 40 minutes have passed.
  • It is 3:30. In 4 hours, it will be 7:30.

Students will also find elapsed time using a calendar. Help students become familiar with the “language” of calendars. Include the days of the weeks, months of the year, and ordinal numbers (first, second, third, and so on) in spelling and language arts activities.

Students apply their understanding of elapsed time in the Problem Solving lesson on Using a Schedule. This is another topic students may find useful in their daily lives.


Houghton Mifflin Math Grade 3