Counting to 100: Tens and Ones
Lessons in this chapter
About Counting to 100: Tens and Ones
Joy of Counting is where place value starts. Up to this point numbers have been things to count; here they become things made of tens and ones.
Represent Numbers up to 20 using Tens and Ones is the lesson the rest of the chapter depends on. Seeing 14 as one ten and four ones is a genuinely new idea, because it means the same digit can mean different amounts depending on where it sits. Everything in later arithmetic rests on this.
Count, Read and Write Numbers till 49, till 79 and till 99 then extend the range in three steps rather than one. The steps are not arbitrary: each one adds a new set of ten-names, and splitting them lets a child get secure before the next batch arrives.
By the end a kindergartener can count, read and write any number to 99 and say how many tens and ones it contains. That is the whole foundation for 1st grade's Numbers to 120 and for every column method that follows it.
Four lessons, each a worksheet opened and worked in the page. Represent Numbers up to 20 using Tens and Ones sets up place value, and Count, Read and Write Numbers till 49, till 79 and till 99 then extend the range in steps rather than all at once. All four are free and marked as you go.
Frequently asked questions
Four lessons. Represent Numbers up to 20 using Tens and Ones introduces place value by building the teen numbers out of a ten and some ones, and the three lessons that follow extend counting, reading and writing to 49, then 79, then 99. The counting sits in Counting and Cardinality (K.CC) and the tens and ones work in Number and Operations in Base Ten (K.NBT).
A way of seeing a number as groups. 14 is one group of ten and four left over, so it is written with a 1 in the tens place and a 4 in the ones place. This is the start of place value.
Because every method kids will use later, column addition, borrowing, decimals, depends on a digit's position telling you its value. Getting the idea in with small numbers makes all of that easier.
Each step adds new ten-names to learn. Doing it in three passes means a child is secure on forty-something before fifty-something appears, which is more reliable than one jump to 100.
Count in tens first, so ten, twenty, thirty, until the ten-names are solid. The ones within each ten follow the same pattern every time, so the ten-names are usually the gap.
Counting, reading and writing to 99 is the target here, and understanding tens and ones matters more than reaching the number 100 itself.