Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
Count forward and backward within 120 given a range. As examples, count from 21 to 44, or count from 115 to 108. Skip count by 10s. Not only 0, 10, 20, but also 4, 14, 24. A good lesson on skip counting by 10s within 120 is here. Make a given number with base ten blocks or read a number from a given set of base ten blocks. Watching this video may help. Write numerals within 120. As the teacher, speak the number and have the student write it down, or give the child an incomplete sequence of written numerals and have them complete it. If you have access to the book The Very Hungry Caterpillar, you can do this:
Read The Very Hungry Caterpillar to your students. Have them guess how many things the caterpillar ate. Then give your students three ten frames and 30 counters each. Read them the story again, having them place a counter for each thing eaten by the caterpillar. At the end of the story, ask them how many things the caterpillar ate. Using an understanding that three filled ten frames is 30, they should quickly respond 31.
Conclude by leading this investigation, which will give your students lots of practice writing 1-25.