Number-line games teach children where numbers fall in relation to larger and smaller numbers. Compete with your class to see if they can read your mind by giving students clues such as "I'm thinking of a number smaller than 15" or "My number is bigger than 2" and invite them to guess what your number is. Use the number line to note the numbers that students have already guessed, and let the student who determines the correct number select a mystery number of his own. Another number-line activity involves giving students an assortment of numbers and having them work together to build their own number line, by putting them in the correct order.
Simple card games reinforce number-sense skills for first-graders. Have pairs of students play a simple game of war, with the student putting down the card with the highest number being the winner of the round. Once students understand the activity, make the game more complicated by inviting a third student to join in the game, or change the rules so the child with the lowest card wins.
Another card game, the One Up or One Down game, involves giving each student five cards and setting the extra cards face down on the table. Turn the top card over, and invite students to place a card that is either one number higher or lower than the number on the table. If none of the students are able to play a card, a second card is turned over from the pile. For example, if a 7 is displayed, students are able to discard either a 6 or an 8. Only the first student to put a card down is able to play, and then the card she placed on the table is the card that must be played to. If she plays a 6, the next card placed must be a 5 or 7. The game continues, with each student who makes a play drawing a card from the pile, until all of the cards have been used.
A pair of dice leads to simple number-sense games in the first-grade classroom. Divide students into small groups, and give each group a pair of dice to play the Odd or Even game. Have them take turns rolling the dice, with the child who is rolling the dice predicting whether the number rolled will be odd or even. If he is correct, he gets to add the numbers displayed on both dice and keep the points. Give students a set number, such as 25 to play to, or let them play for a set period of time.
The Dozen Dice game involves students rolling a pair of dice to collect the numbers 1 through 12 in numerical order, one roll of the dice at a time. For example, if a child rolls a 1 and a 6 on his turn, he is allowed to write down 1 but cannot record the 6. If he rolls a 1 and a 2 on his next turn with the dice, he is allowed to write down the 1 and 2 and add the numbers together and record 3 as well, before passing the dice to the next player.
As first-graders become more comfortable with addition and subtraction skills, number-sense games help them review these concepts. A simple game involves giving each student a worksheet with several math problems and letting students race against each other to finish the paper the quickest. For a more interactive game, have students complete simple addition and subtraction tasks as part of a game of Mother May I, by giving them tasks such as "take 4 plus 2 steps forward" or "hop 5 minus 1 times."