Students learn to recognize written numerals from 1 to 100 and associate them with their spoken names. Understanding how to read numbers up to 100 is essential for working with larger quantities and beginning to understand place value.
You already know how to recognize numbers from 1 to 20, matching each written numeral to its spoken name and to a quantity. Now we are going further — all the way to 100. The good news is that numbers from 21 to 99 follow a very clear pattern, so once you see it, you do not have to memorize each one separately.
Look at the numbers 21, 31, 41, 51, 61, 71, 81, 91. They all end in 1. The first part tells you the "tens" group: twenty-one, thirty-one, forty-one, and so on. The first digit (2, 3, 4, 5, 6, 7, 8, 9) tells you how many tens, and the second digit tells you how many ones left over. So 47 means "four tens and seven ones" — forty-seven. This pattern holds for every two-digit number from 21 to 99. Once you notice it, reading any number in that range becomes a two-step job: read the first digit (the tens), read the second digit (the ones), and say the name.
The special cases are the round numbers: 20, 30, 40, 50, 60, 70, 80, 90. These are called the decade numbers, and their names are twenty, thirty, forty, fifty, sixty, seventy, eighty, ninety. Notice that some of them sound like the ones they count (four → forty, six → sixty, seven → seventy, nine → ninety) and a few look or sound a little different (two → twenty, three → thirty, five → fifty, eight → eighty). These are worth spending extra time on because they are the anchor points of the whole system.
And then there is 100 — one hundred. It is the first three-digit number, and it gets its own special place at the end of the chart. Writing 100 means "ten tens" — ten groups of ten — and it is the biggest number in this range. Knowing where 100 sits helps you feel the size of the number system you are learning: 1 all the way to 100 is a long journey, and being able to read any number in that range means you understand the whole first hundred. This understanding of tens and ones is the beginning of place value, a big idea you will use in almost every math topic from here on.