Number twenty using tally marks written on a blackboard with chalk
Size: 3264px × 2448px
Photo credit: © heliography / Stockimo / Alamy / Afripics
License: Royalty Free
Model Released: No
Keywords: 20, blackboard, chalk, chalkboard, counting, hash, lines, mark, marks, numeral, school, stockimo, system, tallies, tally, tallying, twenty, unary