Lühikesed sammud sihtmärgini
Matemaatika mõisted
Adding 1-digit to 2-digit numbers
materjalid
Playing cards. Paper. Pencil.
Mängijad
2- 4
Luua
Use playing cards with the numbers from 1 to 9.
mängima
For each turn, create a random 2-digit starting number using two playing cards. The first card will give you the tens place and the second the ones place. Starting at that number, you are allowed to use a total of 5 jumps each of which is either by 1 or 10. The goal is to get as close to 50 as possible. The player’s score is the difference from 50.
Eesmärk
The lowest total score after several rounds wins.
Näidiskäik
If the random number is 23, the student must decide whether to use two or three 10’s. Two 10’s moves the number to 43, and three more 1’s gets it to 46. On the other hand, three 10’s moves the number to 53, and taking two 1’s away moves that to 51.
Arutelu ja nõuanded
Discuss strategies for deciding how many 10’s to use.
Young players benefit from referring to a 100-chart. Using that chart will also emphasize place value as they go up or down by 10.
Variatsioonid
Vary this game by allowing steps of 1, 2 or 10, or steps of 1, 2, 5, or 10. Use any other collection of steps that give good adding practice or that seem like fun to your students.
Use target numbers other than 50 sometimes.