• Display 6 red counters and 4 yellow counters.
• “Here are the counters from a round of Shake and Spill. There are 6 red counters and 4 yellow counters. What equations can I write to represent the counters?” ( and )
• “Why do both equations represent the counters?” (You can start with the red or start with the yellow and there are still 10 total counters.)

The purpose of this activity is for students to justify that they have found all the ways to make 10. Students are given access to 10-frames and two-color counters to construct their argument (MP3). Students notice how the addends change and that there are patterns in the numbers in the expressions.

Some students may just start writing equations or placing counters in the 10 frame randomly. Other students may have a systematic way to find combinations, such as placing 10 of one color, such as red counters, on the 10-frame and flipping one counter at a time to yellow (MP6).

• Invite previously identified students to share.
• “How do you know that you found all of the ways?” (I started by filling my 10-frame with red counters and then flipped over the first red counter to make it yellow. That was . I kept flipping over a one red counter at a time to make it yellow and kept writing expressions.)

The purpose of this activity is for students to choose from activities that offer practice adding and subtracting within 10. Students choose from any of the previously introduced stages of the listed centers.

• Number Puzzles
• Check It Off
• Find the Pair

• “What method do you use most often to find the value of sums you do not yet know?”