Numbers to 20
Lessons in this chapter
About Numbers to 20
Numbers to 20 is where counting stops being a list to recite and starts being an order kids can move around in.
Count, Read and Write Numbers from 11-13 takes the awkward part of the number system first. Eleven, twelve and thirteen do not sound like the pattern that follows them, so they have to be learned rather than worked out, and getting them out of the way early stops them tripping kids up later.
Find Numbers that are Before, After and Between is the chapter's real work. It takes the position words from Where Things Are and applies them to numbers, so a child who can say what comes between 14 and 16 is holding the whole sequence in mind, not just reciting forwards from one.
Compare Numbers up to 20 then asks which of two numbers is bigger, which only works once a child trusts the order. This is where counting turns into something usable, and it is the step that Counting to 100 and all of first grade's number work rely on.
Three lessons, three worksheets, all worked in the page. Count, Read and Write Numbers from 11-13 handles the teen numbers that do not sound like the way they are written, Find Numbers that are Before, After and Between turns the count into an order, and Compare Numbers up to 20 asks which of two is bigger. Free to practice online, and scored as you go.
Frequently asked questions
Three lessons. Count, Read and Write Numbers from 11-13 starts with the teen numbers, which are the hardest because their names do not match the way they are written. Find Numbers that are Before, After and Between then treats the count as an order rather than a list, and Compare Numbers up to 20 asks which of two numbers is bigger. It sits in Counting and Cardinality (K.CC) in the Common Core.
They break the pattern. Twenty-one and thirty-one announce their tens, but eleven, twelve and thirteen do not, so kids have to learn them by name. The first lesson covers exactly those three for that reason.
Because it is the difference between reciting numbers and understanding their order. A child who can only count forwards from one has to start over every time; one who can say what comes after 16 is using the sequence.
Before, after and between are introduced in Where Things Are using objects, then reused here with numbers. Same idea, different material, which is why that chapter comes first.
By position in the counting sequence: the number you say later is the bigger one. Comparing digits place by place comes later, once place value is in.
Not as a separate skill at this stage, but finding the number before something is a small step in that direction and it makes subtraction easier when Take Apart arrives.