A child determines a given quantity of blocks and then finds the new amount as blocks are added to the set. She shows us she can say number words in order to eight (stable order), touch and count each cube she has on her mat (one-to-one tagging) and count the blocks in any order while making sure she counts all of them (order irrelevance). However, she is not yet secure yet in her understanding of cardinality. Each time she is given a new block, she starts counting all the blocks from the beginning. This stage of counting is know as the “count-all” stage. When she can hold the cardinal value of a set in her head, then she will be able to count-on when more objects are added.
Focus on the Child videos are taken from one-on-one interviews with individual children. The interviews are designed to elicit evidence of children’s mathematical thinking. They are not teaching episodes or formal assessments.