Kindergarten Spring Math — Compose/Decompose to 10, Addition & Subtraction within 10, Teen Numbers as Ten-and-Ones, Measurement, and Classification
Lesson 6 30 min math.gK.s.lesson_06

Make Ten — Using the Rekenrek (Soroban Connection)

Skills targeted
Objectives
  • Students can use the rekenrek to show ten as 5 + 5 (one full row) and to decompose 10 in multiple ways.
  • Students can find the 'partner of ten' for any number 1-9 (e.g., '6 needs 4 more to make 10').
  • Students see the connection between the rekenrek and the Japanese soroban abacus (cultural anchor).
Vocabulary
rekenreksorobanabacuspartner of tenbeadrow

Lesson plan

Warm-up

5 min

Rekenrek flash: teacher shows 7 beads pushed (5 red + 2 white). Quick flash for 3 seconds. 'How many? How did you see?' Repeat with 8 (5 + 3), 9 (5 + 4), and 6 (5 + 1).

Teacher moves
  • Use the 5-bead anchor explicitly: 'The five reds are always there as our anchor. The whites tell us the extras.'
  • Sentence frame: 'I saw ___ as five and ___.'

Direct instruction

8 min

Today we use the rekenrek to find partners of ten. Watch: I slide all 10 beads to the left (5 red + 5 white on row 1, but our rekenrek only has 10 beads on one row). Ten beads — but I see them as 5 red and 5 white. Five and five make ten. Now if I slide back 4 beads to the right, I have 6 beads on the left. The PARTNER of 6 to make 10 is — 4. Watch again: slide back 3 beads. Now 7 beads on the left. Partner of 7? — 3. And here's something amazing: this tool, the rekenrek, comes from an old Japanese tool called the SOROBAN. (Show soroban.) See how the soroban has ONE bead on top worth FIVE, and FOUR beads on bottom each worth ONE? Same idea — five and some more. People in Japan and China have been using the soroban for hundreds of years.

Key examples
  • Eight needs two more to make ten.
    model 8 = 5 + 3. Partner of 8 = 2.
    prompt Slide rekenrek to show 8 beads on left
  • Four needs six more to make ten.
    model 4 = 4 + 0. Partner of 4 = 6.
    prompt Slide rekenrek to show 4 beads on left
  • The soroban shows 7 as 'one five and two ones.' Our rekenrek shows 7 as 'five reds and two whites.' Same idea!
    model 5 + 2 = 7 on the soroban.
    prompt Show soroban with 1 heaven bead + 2 earth beads pushed
Checks for understanding
  • Show me 9 on your rekenrek. Now show me the partner of 9 to make 10. (Listen for child to slide back 1.)
  • What's the partner of 3 to make 10? (Listen for '7'.)
Media
M-K-S-AT-06-A Photograph
Studio photo, plain white background. Left: a 10-bead single-row rekenrek (5 red beads + 5 white beads on a wooden frame

Studio photo, plain white background. Left: a 10-bead single-row rekenrek (5 red beads + 5 white beads on a wooden frame) with all 10 beads pushed to the left. Right: a Japanese soroban with 1 heaven bead and 2 earth beads pushed to show '7' in soroban notation. Caption below: 'The rekenrek (left) and the soroban (right) — both show numbers as FIVE and some more.' Style: clean product photography, even lighting.

M-K-S-AT-06-C Diagram
Six small diagrams (one per pair) in a 2x3 grid. Each diagram shows a 10-bead rekenrek with one configuration — top-left

Six small diagrams (one per pair) in a 2x3 grid. Each diagram shows a 10-bead rekenrek with one configuration — top-left (1 on left + 9 on right), top-middle (2+8), top-right (3+7), bottom-left (4+6), bottom-middle (5+5 with the red-white split visible), bottom-right (0+10). Each labeled with its equation: '1 + 9 = 10', etc. Style: schematic, color = red beads + white beads, no shadows.

Guided practice

10 min
Tasks
  • Partner Make-Ten game: Partner A flashes a number 1-9 on a flash card. Partner B shows that many beads on the rekenrek, then states the partner of 10 ('I need ___ more to make ten'). Swap roles after 5 rounds.
    scaffold Pre-printed partner-of-10 reference card for children new to the relationship.
  • Class chant: teacher calls a number; class chants the partner of 10 ('Teacher: SEVEN. Class: THREE!').
    scaffold Slow tempo first, speed up after 3 rounds.
Media
M-K-S-AT-06-B Video Physical / non-image

Two children seated face-to-face on a rug. Child A holds a flash card showing the numeral '7' and shows it to Child B. Child B slides 7 beads on her rekenrek to one side, then says aloud (with subtitle overlay): 'I need three more to make ten!' Camera zooms in on Child B's rekenrek showing 7 beads. Music: gentle xylophone. Voiceover: 'The Make-Ten partner game.'

Formative assessment

2 min
Exit ticket
  • Fill in the blank: 6 + ___ = 10
  • Fill in the blank: 3 + ___ = 10
  • Show 8 on the rekenrek and tell the partner of 8 to make 10.
scoring 3 of 3 correct = mastery; 2 of 3 = practicing; ≤1 = reteach with rekenrek and partner-of-10 card next session

Closure

Moves
  • Math Detective close: 'Now we know partners of ten! Tomorrow we use them to ADD bigger numbers — like 7 + 4 — by MAKING TEN first.'

Homework

5 min
Tasks
  • Practice the partner-of-10 chant with a grown-up. Try to recite all 6 pairs in 10 seconds. Bring a recording (paper-mark or oral report) to school.

Exercises in this lesson

math.gK.s.ex_15
Show 9 on the rekenrek. How many more beads do you need to make 10?
 rekenrek show · diff 2
math.gK.s.ex_16
Draw a line between each number and its PARTNER of 10. (Provided: numbers 1-9 on left, numbers 1-9 on right, child draws matching lines.)
 partner match · diff 2
math.gK.s.ex_17
Fill in: 4 + ___ = 10
 missing addend · diff 3

Differentiation

Scaffolds
  • Color-matched partner cards (each partner pair same border color: 7-and-3 both have red borders, 6-and-4 both blue, etc.)
  • Fixed-position rekenrek with partner positions pre-marked
  • Linking cube ten-train (10 cubes snapped together) for fixed-decomposition
Extensions
  • Partners of 20 (15 + 5, 12 + 8) using a double rekenrek as a stretch toward G1
  • Find partners of 5 (a smaller version): 2 + 3, 1 + 4, 0 + 5
English Learners
  • Bilingual partner-of-10 cards
  • Audio chant of partners
  • Picture-based partner flash cards
Ieps 504s
  • Pre-positioned rekenrek with one hand-position cue
  • Reduced range (partners 1-5 only on first attempt)
  • Magnetic rekenrek on a vertical surface for fine-motor support

Teacher notes

Today connects the rekenrek (Western K-12 math tool) to the soroban (East Asian abacus tradition). This is the culturally-responsive math moment — children see that the 'five and some more' decomposition is centuries-old across cultures, not a new American invention. Partner-of-10 fluency is the keystone of Grade 1 'make ten to add' strategy; the more fluent children are by end of K, the smoother Grade 1 will be. Make this chant a transition routine (line up by saying partners). Some children will know partners better than others — group flexibly. The partner-of-10 cards are a reusable resource for the rest of the year.