Counting and cardinality
How do counting words, said in order and matched to things, come to tell how many there are?
Where you are 23 inside
What this area is about
A number names how many. Counting gets there by matching each thing to one counting word, in order, with none skipped or said twice; the last word said is the size of the whole group. Then the words stretch to 1{,}000, take written form, and let two amounts be compared.
How these fit together
The words. Counting words to 20, to 100, to 120, past 100, skip counting.
Counting things. One-to-one correspondence, counting a set, how counting tells how many, counting out a number, one more and one less, counting on and back, counting a large pile by grouping, subitizing and ten frames.
Writing and naming. Names, numerals and zero, writing numerals, ordinal numbers, the number line, even and odd.
Comparing. Comparing groups, comparing numbers to 10, >, < and =, the equal sign.
A path through it
Say the words to 20, match one to one, count a set, then learn that the last word tells how many. Counting out, one more, counting on, and names and numerals follow; writing numerals and ordinals come after names. Subitizing precedes ten frames, and comparing groups precedes comparing numbers. Counting to 100 opens skip counting, 120 (once numerals are written), 1{,}000, even and odd, and, after skip counting, grouping and the number line.
Next come addition and subtraction and place value.