66 2013–2014 MATHCOUNTS Club Activity Book

Buzzer BlitzMOST

POPULARGo head-to-head to see who is the quickest to the buzzer!

The Countdown Round of the MATHCOUNTS Competition Series is often considered to be the most fun and exciting part of competition day, but only a handful of students get to participate. Now every member of your club can have a great time participating in this just-for-fun version of a Countdown Round.

MATERIALS NEEDED • Countdown Round PDF presentation (available for download at www.mathcounts.org/ClubLeaders)• LCD projector/laptop OR overhead projector/overhead transparencies of the Countdown Round PDF

presentation slides• Stopwatch• Buzzers (optional)• Prizes for winning students/teams (optional)

HOW IT WORKS At www.mathcounts.org/ClubLeaders you can download a PDF presentation with more than 100 Countdown Round problems. These particular problems are from previous years’ School Countdown Rounds. During an official competition, students play against each other (one on one) to see who can answer each question first. There is a 45-second time limit for each problem. The student who correctly answers the most out of three questions moves on to play the next student. (There are many more of these files available through the MATHCOUNTS Store at www.mathcounts.org/store. However, keep in mind that the questions will get more difficult as you progress to the state and national level questions. Some chapter level questions will be slightly harder than school level questions.)

Feel free to use these problems in any way you would like. Some coaches have used the following arrangements.

TEAM VS TEAM

Divide the club into two teams. Each team has a “MATHCOUNTS buzzer” (which can be a rolled-up piece of paper that can be used to slap the desk when the team has the answer). The buzzer is passed from team member to team member so that there is a different person using it each time for each team. A question is shown on the screen, the two teams work on the problem and when a student has the answer, he runs to tell the keeper of the buzzer to use it. Then the answer is given. If the answer is correct, the team gets 2 points. Some questions are very straightforward, but for some of the more complex questions, the teacher can offer 1 point to the other team if any member can explain how to solve the problem after the answer has been given.

TEAM REP VS TEAM REP

Divide the club into two teams, and have each member of each team draw from a hat the numbers 1, 2, 3... randomly, without replacement. The two 1s then play each other (best of three), then the two 2s, and so on. A team earns a point when its member wins a head-to-head competition. After everyone has had a turn, all of the numbers are put back into the hat and new numbers are selected. Thus, new match-ups are made. The winning team gets a prize.

2013–2014 MATHCOUNTS Club Activity Book 67

STUDENT VS STUDENT (bracket style)

With a smaller club, you can randomly place the students’ names into a bracket and have them play one-on-one until a winner is determined. The winner could receive a small prize.

EVERY STUDENT PLAYS AT ONCE

Have all students participate at once, but all of the students write down their answers rather than buzzing in and yelling them out. Show the problems one at a time, and leave each problem displayed for 45 seconds before moving to the next problem. After 15 problems, determine who has the most correct answers (or which team has the most correct answers).

If your students really enjoy this kind of activity, consider having a Countdown Round competition of some sort at the end of every meeting!

SAMPLE PROBLEMS (10 of 100+)

Half of 12 is equal to what number?

What is the smallest positive integer that can be added to 100 to make a multiple of 3?

What is the greatest common factor of 40 and 48?

If the last two digits of 9567 were interchanged, how much larger would the new number be?

The average of five numbers is 10. Four of the numbers are 10, 10, 10 and 9. What is the value of the fifth number?

In training, Petra runs 1/6 of a mile in 60 seconds. At this rate, how many seconds does it take Petra to complete a run of 1 mile?

The area of a square is 49 square centimeters. How many centimeters are in the perimeter of the square?

What is the remainder when 4697 is divided by 9?

In any month with a “Friday the 13th,” what day of the week is the first day of the same month?

What is the greatest integer less than (−17)/4?

The buzzer round (Countdown Round) at MATHCOUNTS competitions is often seen as the most fun part of the day. These students are participating in the National Competition

Countdown Round, student vs student.

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