Lakeshore Subtraction Machine

Lakeshore Subtraction Machine for kids Good used condition. Great for car rides and a nice alternative to screens. "Our self-checking Subtraction Machine makes math so simple, kids can teach themselves! Children just press the equation buttons…and the answers pop up for immediate reinforcement! You get 81 equation buttons locked securely into the 8 1/2" x 9 1/2" plastic frame." math, subtraction, kindergarten, 1st grade, 2nd grade, homeschool