To play subtraction bowling, you'll need nine bowling pins made out of empty 2-liter soda bottles. Line them up as you would bowling pins and have students stand about 5 feet away. Allow the students to take turns bowling, using a small ball, then have them write the equation. For example, if a student knocks down six pins, she would write "9 - 6" and try to figure out the answer. Each player gets two turns to bowl, and must write and answer a subtraction equation based on how many pins they knock down. To show an equivalence of adding, have the student then take the difference they found just before and add it to the original number of pins they knocked down to get the total number of pins. So the student who knocked down six pins would add "3 + 6" to get a total of nine pins.
Adding and subtracting isn't always easy for the beginning math student. For children entering into first or even second grade, learning how to subtract and add equal amounts to an equation can get complicated quickly. Teachers can use simple, entertaining and hands-on games to teach their students the equivalence of adding and subtracting to a sum without solely relying on math drills and worksheets.
"Getting even" addition game
Instead of bowling pins, use playing cards to teach students in groups of two to five how to add. Lay out all of the cards from one deck on one student's desk, face up in an overlapping line. Look for cards next to each other that add up to an even number. Aces equal one point, jacks equal 11, queens equal 12 and kings are 13. Then remove all even sums. Continue until the student can no longer add two remaining cards together to make an even number. Have the student count the remaining cards. If the student can remove all of the cards in subsequent rounds, he or she is the winner. To modify this game for subtraction, look for cards next to each other that, if subtracted, would lead to a difference that is an even number. For example, if a 9 and a 7 were next to each other, the difference would be 2, which is an even number.
Another way to reinforce addition and subtraction uses an empty dozen egg carton, jelly beans or cotton balls and a pair of standard dice for each student. This game is best played in groups of two to five students. The students should number each section of the egg carton in consecutive order, starting with two, until they get to 12, leaving one spot unnumbered and marked with an asterisk (*). For each turn, the student rolls the dice and adds the numbers on the top of both dice. For that number, the student puts a jelly bean or cotton ball in the corresponding space on the egg carton. The asterisk can be used for any number. Then the next student goes and rolls the dice for their turn. The student who fills up all spaces with a jelly bean or cotton ball wins.
Using dominoes can also be a way for the instructor to build up a student's number sense. Take a standard sheet of computer paper and draw a line vertically down the width of the paper, in the manner of a blank domino. Have the student select a domino randomly from a pile, and then recreate the domino on the piece of paper with colorful counter chips. Then have the student identify what total number the domino is by assigning it a number card. For example, if the domino had two dots on one side and three dots on the other, then the student would place a number 5 card by the domino mat he created. To modify this game for subtraction, have the student subtract one side from the total amount and assign a number card to that difference. For example, if the student took away the two dots on one side, he would assign the number card 3.
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