Find the value of each expression mentally.

1. There are students standing in the classroom. 
   Some of the students sit down on the rug. 
   There are still some students standing.

2. There are 15 students standing in the classroom.
   Some of the students sit down on the rug.
   There are still 5 students standing.
   How many students sat down on the rug?
   Show your thinking using drawings, numbers, or words.

1. There are 17 students in the classroom.
   4 students go home.
   How many students are still in the classroom?
   Show your thinking using drawings, numbers, or words.

2. There are 17 students in the classroom.
   Some students go home.
   Now there are 4 students in the classroom.
   How many students went home?
   Show your thinking using drawings, numbers, or words.
   

Choose a center.

Shake and Spill

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