Counting by tens to one hundred

When you reach for it

Counting by tens means saying one word for each whole group of ten: ten, twenty, thirty, and on up to one hundred. It works only when every group really holds ten, so the child first builds the groups with sticks, fingers or full ten frames, and then counts the groups, not the single things. Ten groups of ten make one hundred, which is the end of this week’s count.

The child should already count to one hundred by ones or be learning to, and know that a ten and some more makes a teen number. Each day takes about ten to fifteen minutes.

Day 1: Bundles of ten sticks

You need: about 40 craft sticks (or straws) and some rubber bands.

Count out 10 sticks with the child, one by one, and put a rubber band around them. Say, “This is a bundle. How many sticks are in it?” The answer is ten, and the band means it stays ten, so nobody needs to count it again. Make three more bundles the same way.

Now lay the bundles down one at a time. As each one goes down, say the new count: “ten, twenty, thirty, forty.” Let the child put the bundles down while you both say the words, then let the child say them alone.

Ask, “When I put down one more bundle, how many more sticks are there?” The answer is ten more, every time. Ask, “Is it faster to count the sticks or the bundles?”

Practice.

1. Lay down 2 bundles. Answer: “ten, twenty”, so 20 sticks.
2. Lay down 5 bundles. Answer: the last word is “fifty”, so 50 sticks.
3. Lay down 7 bundles. Answer: “seventy”, so 70 sticks.
4. Cover the numbers in the picture above and count the bundles by tens. Answer: “ten, twenty, thirty, forty”, so 40 sticks.

Day 2: Ten fingers at a time

You need: a few children, or one child and some grown-ups.

First have one child hold up both hands and count the fingers by ones, from one to ten. Ask, “So how many fingers does one person have?” Ten. Then line people up, each holding up all ten fingers. Walk along the line and touch each pair of hands as you say “ten, twenty, thirty” and so on. One word goes with each pair of hands, not with each finger.

Ask, “If one more person joins the line, what will we say next?” The count goes up by ten, because one person brings ten fingers.

Practice.

1. 3 people hold up all their fingers. Answer: “ten, twenty, thirty”, so 30 fingers.
2. 6 people hold up all their fingers. Answer: the last word is “sixty”, so 60 fingers.
3. 10 people hold up all their fingers. Answer: “one hundred”, so 100 fingers. Ten tens make one hundred.
4. Maya counted the fingers of 5 people by ones and got 50. Count the same hands by tens. Answer: “ten, twenty, thirty, forty, fifty”. The count is the same, 50, but it takes only 5 words.

Day 3: Full ten frames

You need: about 10 ten frames and plenty of counters.

Have the child fill a ten frame with counters, one in each box. Ask, “Is there an empty box? So how many counters are on this frame?” A full frame is ten without counting. Fill a few more frames and put them in a row, then count the frames: “ten, twenty, thirty.”

Ask, “How do you know each frame is ten?” The child should say there are no empty boxes. A frame with an empty box is not a ten, so it cannot be counted with a ten word.

Practice.

1. Count Row A by tens. Answer: 30, “ten, twenty, thirty”.
2. Count Row B by tens. Answer: 60, the last word is “sixty”.
3. How many full frames does the child need to show fifty? Answer: 5 frames, one for each word “ten, twenty, thirty, forty, fifty”.
4. Put one more full frame at the end of Row B. Answer: 70, ten more than sixty.

Day 4: All the way to one hundred

You need: 10 bundles of ten sticks from Day 1 (make more as needed).

Lay the bundles down one at a time and count by tens all the way: “ten, twenty, thirty, forty, fifty, sixty, seventy, eighty, ninety, one hundred.” Stop on one hundred and ask, “How many bundles did that take?” Ten bundles of ten are one hundred.

Then write the tens in a row, or show the strip below. Every number in it ends in a 0, because each one is a number of whole tens with no single sticks left over.

Last, start in the middle. Put 3 bundles down at once and say “thirty” without counting them. Then add bundles one at a time and keep going: “forty, fifty.” Starting from a number already on the table is the same move a child uses when counting on.

Practice.

1. Which number goes in the empty box of the strip? Answer: 60. It comes after fifty and before seventy.
2. Start with 3 bundles (“thirty”) and add 3 more, one at a time. Answer: “forty, fifty, sixty”, so 60 sticks.
3. Counting by tens, what comes after ninety? Answer: one hundred, 100.
4. How many bundles of ten make one hundred? Answer: 10 bundles.

Exercises

1. Each bundle in the picture holds ten sticks. How many sticks are there in all? Watch whether the child counts the bundles by tens or tries to count every stick.
2. Put 7 bundles of ten on the table and say “seventy”. Hand the child more bundles and say, “Keep counting by tens until you reach one hundred.” How many more bundles did the child put down?

Where this goes next

Counting by tens is the fast way of counting a large pile: put the things into groups of ten, then count the groups. Reading a bundle as one ten and a loose stick as one leads to Tens and ones, and the tens count gives the products in facts for two, five and ten. Other jumps come with counting by twos and fives, and much later ten bundles of ten are bundled again for counting by hundreds.