standard_description: Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
problem_activity: Stage 1: Add Ones
Required Preparation
Materials to Gather
Connecting cubes in towers of 10 and singles
Number cards 0–10
Materials to Copy
Blackline Masters
Target Numbers Stage 1 Recording Sheet

Narrative
Before playing, students remove the cards that show 0 and 10 and set them aside.
Students add a one-digit number to a two-digit number with composing a ten in order to get as close to 95 as possible. Students start their first equation with 55 and turn over a number card and add it to their starting number for the round. The sum becomes the first addend in the next round. The player who gets closest to 95 in 6 rounds, without going over, is the winner.


aligns: no