Draw a "neighborhood" of homes on the board, and assign each house a number (10, 20, 30, etc). In the neighborhood, every neighbor, and each neighbor's pet has a number. Explain to the students that a new neighbor has just joined the community, and her number is 14. She is looking for a house, and the house that she can live in must be the one that is closest to her number. Ask your students what that number is. Take the game further, and tell your students that a cat and a dog, with the numbers 14.4 and 16, belong to two of the neighbors. Ask them what houses the cat and dog live in.
Draw a mountain on the board, and write the number 5 at the top of the mountain. Write the numbers 1 through 4 on the left side of the mountain, and write the numbers 6 through 10 down the right side of the mountain. Draw a car, driving up the first side of the mountain, and give the car a number (4.5, 6, etc). Based on the number, ask your students whether the car is likely to fall down to one, or go over the top of the mountain and fall to the number 10.
Give each of your students an index card, with a number between 1 and 100 on it. Draw a giant number line on the ground, either by drawing on the ground outside with chalk or by using masking tape indoors. Ask your students to round to the nearest 10. For instance, 50.4 would round to 50, while 56 would round to 60. Have each student position himself on the number line, then have him jump over to the correct position. If a student moves incorrectly, give him another number and have him try again.
Pass out bingo sheets and chips; each student should have a sheet of bingo with different numbers on it. Ask students to round their numbers to the nearest 10, and remind them of what this means. For instance, 50.4 would round to 50, 11 would round to 10, and 16 would round to 20. Call out different round numbers. If students see a number that will round to any of the numbers that you call out, they should place a bingo chip on that number. The student with the greatest number of correctly placed bingo chips wins.