Ones & Tens: Dinosaurs Stomp, Alligators Chomp

Ones & Tens: Dinosaurs Stomp, Alligators Chomp

This resource was created by Big Ideas in Beta, a Big Ideas Fest project, with acknowledgement to Amelia Terrapin


  • Students will explain that 10 equals a bundle of ten ones, called a “ten.”
  • Students will understand that two-digit numbers are comprised of a ten digit and a one digit.
  • Students will use the symbols <,=,> to compare 2 two-digit numbers.


  • 1.NBT.2. Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases: 10 can be thought of as a bundle of ten ones — called a “ten.” The numbers from 11 to 19 are composed of a ten and one, two, three, four, five, six, seven, eight, or nine ones. The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones). 
  •  1.NBT.3. Compare two two-digit numbers based on meanings of the tens and ones digits, recording the results of comparisons with the symbols >, =, and <.



45 minutes 



Less than ten minutes



  • Index cards with two-digit numbers on them        
  • Open space; pushing desks aside is helpful, going outside or to the gym would be ideal


  1. As a pre-assessment, ask the students what they know about two-digit numbers. Write a two-digit number and ask “Can anyone tell how many “tens” and how many “ones” are represented?”  Write the comparison symbols <, =, > on the board.  Ask the students “Can anyone tell me what these symbols mean?”  Allow time for discussion.Ask the students to stand up.  Put a single digit number on the board, for example, 5.  Tell the students that we will stomp our feet like dinosaurs 5 times to represent this number.  Repeat a few times with single digit numbers, stomping and saying the numbers as you count together.
  2. Ask the students “What if I were to write down 20? 50? 90? That’s a LOT of dinosaur stomps.  How could we make this easier and faster?” Write students’ response on the board.  Suggest to the students that we come up with a movement for 10 ones (ex. jump in an X shape).Now write the number 20 on the board.  
  3. Ask the students to count together by tens….one 10, two 10s.  Repeat a few times using only tens (30, 50, 90).  Do the movement you have chosen with each ten.
  4. Next put a number on the board with both a ten and one place digit, for example, 23.  Ask the students “How can we “move” this number using our actions?”  Two “tens” and three “ones” (two jumps in an X, three stomps).  Call on specific students to demonstrate and then do it all together as a group.
  5. Put students into pairs.  Each pair will draw an index card with a two-digit number (be sure each number has a ten and one value: 24, 62, 37 etc, no numbers ending in zero.)  One person will move the “tens” digit with jumps in an X and one person will move the “ones” digit with stomps.  Walk around and monitor students offering feedback where necessary.  After all pairs have had a chance to practice, go around the room and have each pair demonstrate their number for the group.
  6. Tell the students, “Now we are going to look at some comparisons.”  Reintroduce the greater than, less than and equal to symbols on the board with examples.  Talk about the alligator always eating the bigger number!
  7. Ask each pair to hold up the cards with their two-digit number on it.  Choose two numbers that are across the room from each other and ask them to stand up.  Select one person to “be” the > or < symbol and stand up and use their arms to make the sideways “V”.  They will always want to open their “V” in the direction of the bigger number, like an alligator chomping away!  Tell the student, “Move in the direction towards the bigger number while chomping your arms like an alligator!”  Repeat this exercise a number of times with different students as the symbols.
  8. Split the entire group in half.  Write a number on the board for one group, for example, 36.  Ask them to all move it together (3 jumps in an X, 7 stomps).  Repeat for the other group, for example, 52 (5 jumps in an X, 2 stomps).  Select one person to act as the > or < symbol.  Ask them to stand in between the two groups, moving towards the bigger number with chomping alligator arms.  This is a good way to assess those that might need a little extra help. 
  9. For fun you could throw in two of the same numbers and discuss how to compare these numbers.  
  10. Ask the students come up with a = symbol with their bodies!As a post-assessment, ask the whole group to analyze any given two-digit number and ask, “How many tens? How many ones?”  For any two given two-digit number, ask, “Can you use the <, =, > symbol to make a comparison statement about these two numbers?”  Students should respond verbally.  Allow time for discussion while reinforcing the core standards addressed in this lesson. 



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