Place Value to 20: Expanded Form 1-37
Lay the foundation for place value. Start by modeling teen numbers on ten frames. 12 is 10 counters and 2 counters – 10 ones and 2 ones – 12 ones in all. Transition to using Base 10 blocks or snap cubes to "unitize" 10 ones as 1 rod or unit. 12 is now 1 ten and 2 ones – 1 rod and 2 ones – not 12 cubes or counters.
