Comparing Batting Averages: Subtracting to the Thousandths
Students will calculate differences using decimal numbers to the thousandths.
- Ask students to raise their hand if they play baseball or softball.
- Ask students to raise their hand if they are a fan of baseball? Ask follow up questions such as, what teams are their favorites? Who do they think will win the World Series this year?
- Explain that they are going to examine one of the most popular statistics used in baseball - batting averages.
Explicit Instruction/Teacher modeling(10 minutes)
- Teach the class how to calculate batting averages. You can show the short video in the Suggested Media section or teach it yourself, as follows:
- 1) Explain that it is a math equation written as a fraction. The numerator is the number of times the player got a hit. This means the player hit the ball into fair territory and made it to first base (or further) without the help of a fielder error.
- 2) To get the denominator, you subtract the number of number of walks and sacrificial fly balls subtracted from the total amount of times they were up at bat.
- 3) When you have this fraction, you can divide the numerator by the denominator and that will give you a decimal number, such as .31457.
- Tell students that batting averages are rounded to the nearest thousandth, so that example would be .315.
Guided Practice(10 minutes)
- Assign a student to sit at a computer in your classroom with internet access.
- Instruct the student to enter 'Major League Baseball Player Statistics' into the search bar.
- Ask students to name some of their favorite players, taking two at a time.
- As students name players, write their names on the board while the student at the computer calls out their batting averages. Write the averages next to the players.
- Compare the two batting averages by subtracting the two numbers to the thousandths place. Note whose average is better and by what amount.
- Do this process two or three more times until students get the hang of it.
Independent working time(20 minutes)
- Distribute the Batter Up! Compare Batting Averages of Major League Baseball Players worksheet.
- Instruct students to complete the word problems using the statistics tables at the top.
- When done, they can generate two of their own word problems using the statistics.
- Circulate the room to spot check for accuracy and reteach when necessary.
- Provide graph paper so that students can more easily align the numbers’ place values and complete the problems.
- Provide a short mini-lesson on subtraction with one or more zeros in the top number.
- Allow students to conduct research on the statistics that are tracked in their favorite sports. How are they calculated?
- Use a student generated problem from one of the their worksheets to put on the board or project. On the back of their worksheet, have them solve this problem. Remind students to show their work. Spot check student answers for accuracy.
Review and closing(5 minutes)
- Discuss the following questions with the class: How is dividing two numbers to the thousandths different than dividing two numbers to the thousands? How is it the same?