Montessori Math

The Lesson AlbumLinear & Skip Counting · lesson 5ages 5–7grades K–1

The Hundred Board

The child places number tiles 1 to 100, in order, on a ten-by-ten board. It pulls together everything learned about counting past ten and lets the child see the whole landscape of numbers to one hundred laid out in rows of ten.

Materials

  • A hundred board: a 10×10 grid with squares about 1 inch across (a purchased board, or draw one on poster board with a ruler)
  • Number tiles 1–100 (wooden tiles, or cut 100 small squares of cardstock and write the numbers with a marker)
  • A control chart: a completed hundred chart the child can uncover to check their work (print one or write one out)
  • A small tray, bowl, or box lid to hold the loose tiles

No materials at home? Use the virtual Hundred Board.

Before this lesson

Aims

Direct

  • To reinforce the sequence of numbers from 1 to 100
  • To connect counting aloud with reading and ordering the written numerals
  • To show the structure of the numbers to 100: ten rows of ten

Indirect

  • Preparation for skip counting and, later, multiplication
  • Discovery of place-value patterns (every number in a column ends in the same digit)
  • Development of concentration, order, and independent work over a long task

Presentation

  1. 1 Bring the empty board and the tray of tiles to the table. Sit beside the child, with the board square in front of them.Today we are going to build every number from one to one hundred.
  2. 2 Find the tile 1 and place it in the top-left square. Trace along the top row with your finger to show which way the numbers will go.One. The numbers march this way, across the row.
  3. 3 Hand the child the tile 2 and let them place it next to the 1. Continue handing tiles in order — 3, 4, 5 — saying each number together as it is placed.Two. Three. Four. What comes next?
  4. 4 When the child reaches 10 at the end of the row, pause and slide your finger down to the start of the next row.The row is full. Eleven starts a brand-new row, right under the one.
  5. 5 Let the child carry on placing tiles in order at their own pace. Stay nearby but resist correcting — a misplaced tile will announce itself when the pattern stops working.
  6. 6 If the child tires, it is fine to stop at the end of a row and finish another day. The full board can take several sittings at first.We finished the forties today. Next time we can start at fifty-one.
  7. 7 When the last tile is placed, read some rows and columns together. Run a finger down the right-hand column: 10, 20, 30 …Look — every number in this column ends in zero. You built all one hundred numbers.

Points of interest

  • The moment a row fills up and a new one begins
  • Watching the columns emerge: 3, 13, 23, 33 all lined up
  • The very last tile — 100 — completing the square
  • Finding a stray tile because the pattern suddenly looks wrong

Control of error

  • The number pattern itself: a tile out of place breaks the visible order of the row and column
  • Exactly 100 tiles and 100 squares — leftover tiles or empty squares reveal a mistake
  • The control chart, which the child can compare against square by square

Vocabulary

  • row
  • column
  • hundred
  • before
  • after
  • the decade names: twenty, thirty, forty … one hundred

Variations

  • Build just one decade at a time (all the fifties) for a shorter work session
  • Once the board is familiar, mix the tiles in a bowl and place them wherever they belong — the authentic, harder version (the Shuffled mode in the virtual board)
  • Place the tiles counting backward from 100 to 1

Extensions

  • Remove five tiles from a finished board while the child covers their eyes; they name and replace the missing numbers
  • Ask the child to find a spoken number — "Can you put your finger on sixty-three?" — before any tiles are placed
  • Cover a row with a strip of paper and ask what is hidden underneath

Follow-up work (pencil & paper)

  • Print a hundred chart with some numbers missing and have the child fill in the blanks with a pencil.Printable: Hundred Chart Puzzles
  • Write the numbers 1 to 100 in a notebook, ten to a row, so the written page mirrors the board. Spread this over several days.
  • Number hunt on paper: write a decade (for example 41–50) with two numbers swapped, and have the child find and correct the swap in pencil.

What comes next

When the child can build the whole board from mixed tiles, they are ready for Skip Counting on the Hundred Board, where the same board reveals the patterns of counting by twos, fives, and tens. The bead chains follow, giving those same patterns a shape the hands can hold.

Next in this strand: Skip Counting on the Hundred Board