Equivalence Crisis Tray – Montessori Math Lesson
Equivalence Tray – Presentation I
Invite the child to see some new work with the golden beads. Spread a mat: “This is the equivalence tray. Some people call it the Crisis of Nine tray. Let'sd look at these beads and count them. We'll start with the units.”
- Count the units from their tray into the mat below in a vertical line, touching each other.
- “Ten units is the same as a ten bar. When we have a ten bar we have to move to a new place. We can't stay in the unit's place anymore.”
- Use the same approach and language with tens/hundreds and hundreds/thousand: “Ten bars is the same as a hundred square. When we have a hundred square we have to move to a new place…”
Presentation II – Exchanging
- Return to the row of units: “Now, let’s count these again.” Make a big deal of moving to the ten’s place and picking up a ten bar “because ten units are the same as one ten.” Continue on to the thousand cube by counting the hundred squares.
- Summarize and quiz the child: “ten units make what? Ten bars make what?” etc.
Variations
- Use separate mats for each quantity so the child must move his body considerably to count the beads
- Ask the child to give you or to bring to you various quantities. Occasionally ask for ten of something to check if the child understands the exchange.
Extensions
- Make a Take Home Booklet showing equivalence. So, ten units on one page and a ten bar on the opposite facing page. etc
- Draw or color the bead material
Have fun!
Marnie