Step 3 in the Number Core Age 5 or Kindergarten
Integrate All Core Components, See a Ten and Some Ones in Teen Numbers, Relate Ten Ones to One Ten, and Extend the Core Components to Larger Numbers
Children at particular ages/grades may exceed the specified numbers and be able to work correctly with larger numbers. The numbers for each age/grade are the foundational and achievable content for children at this age/grade. The major types of new learning for each age/grade are given in italics. Each level assumes that children have had sufficient learning experiences at the lower level to learn that content; many children can still learn the content at a level without having fully mastered the content at the lower level if they have sufficient time to learn and practice.
Cardinality: Extends conceptual subitizing to a new visual group, a group of tens: can see a ten in each teen number (18 = 10 + 8).
Number word list: Extends to learn all of the decades in order as a new number word list counting by tens; uses this decade order with the decade pattern to count to 100 by ones: says the tens list 10, 20, 30, …, 90, 100; says 1 to 100 by ones.
1-to-1 counting correspondences: Continues to extend accurate correspondences to larger sets; accuracy will still vary with effort: counts 25 things in a row with effort.
Written number symbols: Coordinates knowledge of symbols 1 to 9 to write teen numbers: reads and writes 1 to 19; reads 1 to 100 arranged in groups of ten when counting 1 to 100.
Integrates all of the above for teen numbers so that ten ones = 1 ten, relating the unitary cardinality relationship ten ones + eight ones make eighteen ones to the written symbols 18 as 10 with an 8 on top of the 0 ones in ten.