standard_description: Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten.
problem_activity: Stage 9: Subtract Tenths or Hundredths
Required Preparation
Materials to Gather
Number cubes
Materials to Copy
Blackline Masters
Target Numbers Stage 9 Recording Sheet

Narrative
Students subtract hundredths and tenths to get as close to 1 as possible. Students start their first equation with 2 and take turns rolling a number cube and choosing whether to subtract that number of hundredths or tenths and write an equation. The difference becomes the first number in the next equation. The player who gets closest to 1 in 6 rounds, without going below 1, is the winner.
Additional Information
Each group of 2 needs one number cube.


aligns: no