1
Two tens and some ones
Discover Mathematics: Chapter 5
GoalCount 21 to 25 things as two tens and some ones, and write those numbers.
New words
ten-frame · a box with room for 10 thingstens · full groups of tenones · single things left overtwenty · two tens
Explanation
A ten-frame holds ten things. When it is full, we have one ten. Two full ten-frames make twenty. Look at the stars: two full rows of ten and one extra star. That is twenty-one, two tens and one one. Twenty-two is two tens and two ones, and we go on like this up to twenty-five. To write 21, put the 2 for the tens first, then the 1 for the ones.
Worked examples
Farida colours 22 eggs for Sham el-Nessim. There are two full rows of ten and 2 more eggs.
Malak hangs 25 balloons for a party: 2 tens and 5 ones.
Two full ten-frames hold 20 dots. If Adam puts 4 more dots beside them, he has 24.
Class activity
Chickpea rows. Give the child 25 chickpeas or small stones. Put them in rows of ten on the table: two full rows and some left over. Say: two tens and some ones. Then add one or take one away, and say the new number.
Practice
1
How many butterflies are there?
23
2
How many tens and how many ones are in 24?
2 tens and 4 ones
3
Count the kites. How many are there?
21
4
What number comes after 22?
23
5
Write the number for 2 tens and 1 one.
21