Tidy Number Addition — Manifests

Progression 2 (Years 3–4) Number | Adding to 1 000 using tidy numbers/compensation with zoo delivery manifests.

Duration: 60 mins Strand: Number Context: Feed/gear manifests; restoration equipment Representations: Open number line, PV partition, tidy numbers

Learning Intentions & Success Criteria

Te Mātaiaho: use place value to operate with whole numbers to 1 000 NZC L2–3: add/subtract using tidy numbers Key idea: tidy then compensate

Ākonga are learning to:

Use tidy numbers (round to 10/100) to add efficiently.
Represent addition on open number lines and with PV splits.
Compare tidy-number and standard algorithm approaches.

Success looks like:

I can solve 398 + 27 by tidying to 400 then adjusting.
I can show my steps on a number line and in an equation.
I can explain why my strategy is efficient.

Teacher prompts

“What is the nearest tidy number?”
“What did you add, and what must you take away?”
“How do you know your answer is reasonable?”

Kupu / Vocabulary

tidy number / tau whakapai
compensate / whakatika
adjust / whakarite
round / porowhita
efficient / pai ake
estimate / tata

Materials

Open number line templates; base-10 for checks.
Manifests cards (2–3 addends to 1 000).
A5 Handout: Progression 2 core (addition) or generator “Addition to 1 000.”

Lesson Flow

Hook (5 mins)

Manifest shows 398 kg pellets + 27 kg fruits; ask “How close to 400?”

Teach/Model (12 mins)

Model 398 + 27: 398→400 (+2), remaining 25 = 425; show compensation as +2 -2.
Model 246 + 178 with PV partition (200+100 etc.) and tidy rounding (250 + 174).

Guided Practice (15 mins)

Station A: Tidy then adjust (near hundreds).
Station B: PV split then add tens/ones; compare to tidy method.
Station C: Reasonableness check: estimate then solve.

Independent/Extension (10–12 mins)

Three problems; show tidy steps.
Extension: choose best tidy target (10/100) and justify.
Support: numbers < 500; scaffolded number line.

Exit Check (5 mins)

Prompt: 286 + 59; show tidy steps and final answer.

Place-based options

Hamilton Zoo manifests; Waikato restoration gear totals; tidy around 50/100.

Keep both visual (open line) and numeric (compensation) representations; emphasize efficiency and estimation check.

Differentiation & Support

Scaffolds

Use tidy to nearest 10 only at first.
Provide a compensation table: +2 means −2 after.
Keep totals under 500 with open number line templates.

Extensions

Choose the best tidy target (10 vs 100) and justify.
Use tidy strategies for three addends.
Explain when tidy strategies are not efficient.

Common Misconceptions

Forgetting to compensate after tidying. Remedy: write + then − steps.
Over-rounding and losing accuracy. Remedy: keep track of the exact adjustment.
Confusing estimate with exact answer. Remedy: label estimate vs exact.

Assessment & Evidence

Exit prompt accuracy and clarity of tidy steps.
Observation: Are learners over-rounding or mis-adjusting?

Whānau Connection

Send home a “tidy totals” challenge using shopping prices or sports scores.
Invite whānau to share a real-world total they estimate and then check.

Handout Link

Use Progression 2 core handout (addition) or generator “Addition to 1 000,” 24–28 questions, mix of near-100 and general totals.

Back to Number Sense Journey (Progression 2)