Kindergarten Spring Math — Compose/Decompose to 10, Addition & Subtraction within 10, Teen Numbers as Ten-and-Ones, Measurement, and Classification
Lesson 8 30 min math.gK.s.lesson_08

CGI Story Problems — Separate Result Unknown (8 Cookies, 3 Eaten)

Skills targeted
Objectives
  • Students can re-tell a subtraction word problem in their own words (MP.1).
  • Students can solve a Separate Result Unknown problem with counters, drawings, and equations (MP.4).
  • Students can use the sentence frame 'I had ___, then ___ were taken away, so now I have ___.'
Vocabulary
story problemleftremainingtaken awayseparated

Lesson plan

Warm-up

5 min

Number Talk: teacher flashes a dot card showing 5 dots, then quickly covers 2 of them. 'How many were there? How many are showing now? How many were covered?'

Teacher moves
  • Sentence frame: 'I saw 5, then 2 were covered, so 3 are showing.'
  • Connect: 'This is subtraction. We started with 5 and took away 2.'

Direct instruction

8 min

Yesterday we met the minus sign. Today the Math Detectives get a subtraction STORY. Listen: 'There were 8 cookies on a plate. The dog ate 3 of them. How many cookies are left?' Re-tell time. (Take 2-3 retells.) Now we solve. (Put 8 yellow counters on the story-mat START zone.) Eight cookies. (Move 3 to the discard zone.) The dog ate 3. (Count remaining.) 5 cookies LEFT. Equation: 8 − 3 = 5. Number bond: whole 8, one part 3 (eaten), other part 5 (left).

Key examples
  • Nine MINUS four EQUALS five.
    model 9 − 4 = 5. Act out: 9 children, 4 sit. 5 standing.
    prompt Story: 9 balloons. 4 popped. How many left?
  • Six MINUS two EQUALS four.
    model 6 − 2 = 4.
    prompt Story: 6 fish in a bowl. 2 jumped out. How many in the bowl?
Checks for understanding
  • Did the number of cookies get BIGGER or SMALLER when the dog ate some? (Listen for 'smaller'.)
  • What operation do we use when things are TAKEN AWAY? (Listen for 'subtract' / 'minus'.)
Media
M-K-S-AT-08-A Illustration
Children's book illustration: a yellow plate on a wooden kitchen counter with 8 round chocolate-chip cookies. A friendly

Children's book illustration: a yellow plate on a wooden kitchen counter with 8 round chocolate-chip cookies. A friendly cartoon dog (golden retriever-style) approaches from the right with a happy expression. Bottom of illustration: an empty number bond with 8 in the top circle, ? in the two part circles below. Style: warm watercolor, kindergarten picture-book aesthetic.

Guided practice

10 min
Tasks
  • Pairs work through 3 take-away story problems: (a) 7 ducks at a pond, 3 swim away — how many left? (b) 10 crayons in a box, 4 fall out — how many left? (c) 8 leaves on a tree, 5 fall — how many left?
    scaffold Story-mat with action zones.
  • Compare to lesson 5: 'In lesson 5 the number got BIGGER (Join). Today the number got SMALLER (Separate). Why?'
    scaffold Anchor chart with two columns: JOIN (+) and SEPARATE (−).
Media
M-K-S-AT-08-B Chart
Two-column laminated 18x12 inch chart. Left column header 'JOIN (+) — gets BIGGER' with sample equation '5 + 3 = 8' and

Two-column laminated 18x12 inch chart. Left column header 'JOIN (+) — gets BIGGER' with sample equation '5 + 3 = 8' and an illustration of two groups merging. Right column header 'SEPARATE (−) — gets SMALLER' with sample equation '8 − 3 = 5' and an illustration of one group splitting (3 leaving the rest). Style: red header for JOIN, blue header for SEPARATE, bold equations, clean illustrations.

Independent practice

5 min
Media
M-K-S-AT-08-C Audio Physical / non-image

30-second audio file. Adult voice reads the three story problems slowly with 5-second pauses. Voice emphasizes 'taken away', 'left', 'how many'. Background silent. Available at listening center.

Formative assessment

2 min
Exit ticket
  • Story: 'There were 7 apples in a basket. Liam took 4. How many are left in the basket?' Draw and write the equation.
  • Re-tell the story in your own words.
scoring Correct picture + equation + retell = mastery; 2 of 3 = practicing; ≤1 = reteach

Closure

Moves
  • Math Detective close: 'JOIN problems use +. SEPARATE problems use −. Tomorrow we look INSIDE teen numbers — like 14 — to find a HIDDEN TEN.'

Homework

5 min
Tasks
  • Make up a Separate (take-away) story at home with a grown-up. Use real things (toys, snacks). Bring story to share.

Exercises in this lesson

math.gK.s.ex_21
Story: There are 9 apples on a tree. 4 fall off. How many apples are still on the tree? Build with counters.
 act out separate · diff 2
math.gK.s.ex_22
Story: 8 ducks at a pond. 5 swim away. Draw and write the equation.
 draw separate story · diff 2
math.gK.s.ex_23
Story: 10 crayons in a box. Liam takes 3 out. How many are still in the box? Write the equation with the answer.
 write separate equation · diff 3

Differentiation

Scaffolds
  • Pre-arranged counter sets
  • Visual story cards
  • Sentence-frame card for retell
Extensions
  • Mixed Join/Separate: 'I had 6. 3 more came. Then 4 left. How many now?' (6 + 3 − 4 = 5)
  • Make-up your-own Separate story
English Learners
  • Bilingual story cards
  • Picture-rich versions
  • Audio read-aloud
Ieps 504s
  • Concrete-only response
  • One-step problems only
  • Story-mat with arrow scaffolding

Teacher notes

Second CGI lesson — Separate Result Unknown. The retell-before-solve protocol is non-negotiable; this is where children build problem-comprehension as a habit. Compare-and-contrast with Join (lesson 5) is the major take-away: the OPERATION (+ vs −) follows from the STORY ACTION (joining vs separating). Children who keyword-trap ('left' = subtract) without understanding the action need extra concrete modeling. Tomorrow's lesson (9) shifts to teen-number place-value work — the most conceptually demanding piece of the unit.