The longer I teach math, the more I realize the importance of encouraging my students to use “Mental Math” when it comes to the calculation of basic computations. The use of pencil and paper is quite often unnecessary, and can lead to confusion and the making of careless mistakes. When students realize that they can solve problems “in their heads,” it is a huge confidence booster for them, and they marvel at how quickly their brain can calculate basic computations. There is a terrific math game you can play with your students that encourages the use of Mental Math. It’s called “Roll 7,” and has been a favorite game for students for many years.
Have the students draw a vertical line down the middle of their paper. They cross the vertical line with six short horizontal lines. They place a longer horizontal line underneath the vertical line, and draw a box underneath that line. The students have created two vertical columns. The right hand column is the “ones” place. The left hand column is the “tens” place. You draw the same thing up on the whiteboard. If you look at the drawing horizontally, you’ll see that you’ve created seven spaces from the top line to the bottom line – which stands for “equals.” The box underneath the equal line is used to add up all of the numbers. Finally, put a + sign to the left of the drawing because students will be adding up their numbers.
The object of the game is to get a perfect score of 100, or to get as close to 100 as possible without going over! The students who get a score of 100, or the ones who come as close to 100 without going over are the winners. I put the words “without going over” in bold because this is a key concept in how the game works. Here’s how you play:
Roll just one of the dice. Let’s say a six comes up. The students each have to make a choice. If they put the six in the right hand column, they have a score of six. But if they put it in the left hand column, they have a score of 60, because they put the six in the tens column. Let’s assume that the six was put in the tens column, so the score is 60. The first round is over.
Before you roll the dice again, every student MUST have made their choice. No one is allowed to “see what happens,” with the next roll before choosing. Students may also NEVER change their number once they have put it in. Now it’s time for the second roll. Let’s say a one comes up. Once again, the students have to make a choice. Should they put it into the ones column, or into the tens column? Let’s assume that you put the one in the tens column. If you add the two numbers, you have a score of 70 after the first two rounds. The next roll is a five. Since you can’t go over 100, the five MUST go in the ones column. The score is now 75. The next roll is a two. This makes for an interesting choice . . . because the two can go in either column. Let’s play it safe and put the two in the ones column. The score after four rounds is now 77. The next roll is another one. Let’s put that in the tens column. The score after five rounds is now 87. The next roll is a four. This time, the four MUST go in the ones column because you can’t go over 100. The score after six rounds is now 91. The seventh, and final, roll is a six. Again, the six must go in the ones column. The final score is 97 – which goes in the box at the bottom of the drawing. 97 is a good score, and is usually good enough to win. Usually, more than one student will have the highest number. Getting a score of exactly 100 requires skill and a lot of luck, so whenever someone does get 100, they get a Hershey’s Kiss from me!
Students love this game, and it really does promote the use of mental math and mathematical strategy. I hope you give it a try! Below are some other lesson plans that encourage the use of mental math.
Mental Math Lesson Plans and Worksheets:
Students utilize the book “Betcha!” by Stuart J. Murphy as a springboard to help them practice their mental math skills. This incredibly thorough and well-thought-out lesson plan is geared toward third graders. They engage in estimation activities, rounding, and adding up sums of money in their head based on what’s happening in the book. You won’t find a better lesson than this!
Math Games for Number Sense in Grades One Through Three
This is actually many lessons in one! The author has presented a variety of math games geared toward K – 3 students which develop number sense by using mental math. As with my Roll 7 game, the games that are outlined in this lesson should be enjoyable and motivating for your students to play.
Hit The Target
Upper-elementary students participate in an activity to use mental arithmetic to add or subtract simple decimals. This is another math game that is led by the teacher, and has students work in cooperative groups. This innovative lesson should help students grasp the concept of how to add and subtract decimals from the tenths to the thousandths.
Algebra: Use Mental Math to Solve Equations
Upper-elementary students utilize mental math skills when solving these simple algebraic equations presented in this worksheet. Sometimes, insisting that students not use their pencils and paper is the best way to get them to try using mental math. This fine worksheet will give them this type of practice.