Counting Past 10 — Why Ten is So Special (Count to 100 by Tens)

Whole-class chant: count by tens to 100. 'Ten, twenty, thirty, forty, fifty, sixty, seventy, eighty, ninety, one hundred.' Teacher points to each multiple on the 100-chart as the class chants.

• Repeat 3 times at increasing tempo
• Then ask: 'When we count by tens, how MUCH does the number grow each time?' (Listen for 'ten'.)

Yesterday we found that teen numbers are 'ten and some ones.' Today we go further: we count by TENS — all the way to 100. Watch the 100-chart. (Point.) Look at the LAST column: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100. Each one is a MULTIPLE of ten. Now look at linking cubes. (Hold up a 10-train.) One 10-train = 10. Two 10-trains = 20. Three 10-trains = 30. (Hold up multiple trains.) As I add a 10-train, the count goes up by 10. This is why TEN is so special in our number system — everything is built on tens. (Show 100-bead string.) Same idea — 10 white beads, then 10 red, then 10 white. Each group is a TEN.

• Three tens make thirty.

  model Three 10-trains stacked = 30. Count: 10, 20, 30.

  prompt Show 30 with linking cubes
• Six tens make sixty.

  model Six 10-trains = 60. Count: 10, 20, 30, 40, 50, 60.

  prompt Show 60 with linking cubes
• Ten tens make one hundred. That's why this is the 100th day of school countdown!

  model Ten 10-trains = 100. Or the full 100-bead string.

  prompt Show 100 with linking cubes and 100-bead string

• If I have four 10-trains, what number am I showing? (40.)
• How many 10-trains do I need to show 70? (7.)

MG-2 Chart Physical / non-image

Number-Bond anchor chart: a 24-inch poster showing the canonical number-bond visual — a whole circle on top labeled '7', two lines descending to two part-circles labeled '5' and '2' — with the word 'WHOLE' above the top circle and 'PART' under each lower circle. Below the diagram three example bonds for 7 are shown: (5,2), (4,3), (6,1). Used daily as the reference for number-bond work; child-height mounted.

M-K-S-NS-10-A Chart

Standard 10x10 grid 100-chart (the K-Fall MG-2 chart) with the rightmost column (10, 20, 30, 40, 50, 60, 70, 80, 90, 100) highlighted in bright yellow. Each highlighted cell additionally has a red circle around the numeral. Large 28-pt font numerals. Style: clean, white background, primary colors for highlights.

M-K-S-NS-10-C Manipulative Physical / non-image

Photo of a 100-bead string stretched across a child-height surface. Color pattern: 10 white beads, 10 red beads, 10 white, 10 red, ... alternating. A child's finger touches the boundary between the 5th and 6th color group, where the count would say 50. Caption: 'Each color group = 10 beads. Counting by groups: 10, 20, 30, ...'

• Skip-Count-by-Tens game: in pairs, take turns calling a number and the partner names the next 'count-by-tens' number (Partner A: '20'; Partner B: '30'). Use the 100-chart as reference. Continue around the room.

  scaffold Visual 100-chart at child-height for tracking.
• Linking-cube build: each child receives a target number (20, 30, ..., 90, 100) and builds it with 10-trains. Hold up build for class verification.

  scaffold Pre-built 10-trains so children only have to count the TRAINS, not individual cubes.

• Count by tens from 10 to 100 (orally to the teacher).
• Show me 40 with 10-trains.

• Math Detective close: 'TEN is the building block of our number system. The 100th day of school is coming — we'll celebrate with 100 of everything!'

• Practice counting by tens to 100 with a grown-up. Find 'ten of something' at home (10 fingers, 10 toes, a sheet of 10 stickers) and report how many you found.