Ordering two-digit numbers

Overview

Today students will practise ordering two-digit numbers using number lines and place value tools. They will explain their thinking using “tens first, then ones”.

Learning intentions

• WALT order two-digit numbers effectively.
• WALT recognise that tens are more important than ones when comparing numbers.
• WALT use concrete materials and representations to place numbers in order.

Success criteria

• I can arrange two-digit numbers from smallest to largest (and/or largest to smallest).
• I can say which number is bigger and explain why using tens and ones.
• I can use a number line or place value cards to check my ordering.
• I can correct mistakes when I notice the order does not match tens and ones.

Curriculum links

• Ordering and comparing numbers using place value for whole numbers.
• Representing numbers on number lines and using efficient strategies to compare.
• Using mathematical reasoning and explaining choices with number facts and place value.
• Building fluency with counting, ordering, and comparing in the 0–99 range.

Lesson structure (30 minutes)

1. 2 mins – Warm-up (counting and talk)

• Display 5–8 number cards (e.g., 12, 20, 15, 21, 19). Students do a quick “think-pair-share”: Which is greatest and why?
• Teacher prompts: “Look at the tens first—what do you notice?”

2. 6 mins – Explicit teaching (tens-first method)

• Teacher models ordering using place value blocks (tens sticks and ones cubes).
• Use a short example: Order 34, 29, 31. Show that 34 and 31 have 3 tens (so compare ones), while 29 has 2 tens (so it is smaller).
• Record a simple rule on the board: “More tens means bigger. If tens are the same, compare ones.”

3. 8 mins – Guided practice (number line ordering)

• Give pairs a paper number line from 10 to 30 (or 40 depending on class readiness) with 1-step marks.
• Students place 4 numbered cards onto the line to form correct order, then draw arrows showing the sequence.
• Teacher circulates using sentence starters: “I know ___ comes first because ___ tens is smaller/greater than ___ tens.”

4. 7 mins – Hands-on stations (concrete to pictorial)

• Split the class into 3 small groups with rotating roles:
• Station A: Place value cards (tens/ones) to build each number, then order them.
• Station B: Jumbo number line tiles to physically move numbers into order.
• Station C: “Sort and justify” sheet where students write a reason using tens/ones.
• Remind: “Check with the number line—does the arrow move left to right correctly?”

5. 5 mins – Whole-class share and correction

• Select one group’s ordering and ask: “What strategy did you use?” and “Is there another way to check?”
• Teacher corrects common misconceptions (e.g., students mixing ones when tens differ). Re-teach briefly using one quick example.

6. 2 mins – Exit ticket (individual check)

• Students complete one ordering task: “Put these in order from smallest to largest: __, __, __, __.”
• Include a mix where tens differ for some students, and a mix where tens match for others (teacher chooses based on readiness).

Resources

• Place value tens sticks and ones cubes (or base-ten blocks)
• Number cards for 2-digit numbers (10–99 as appropriate)
• Large number line (10–30 or 10–40 depending on your group)
• Paper number lines with 1-step marks
• Place value cards showing tens and ones (e.g., 3 tens, 7 ones)
• Jumbo number line tiles or laminated number strips
• Station worksheets with “reason” prompts
• Teacher sentence starter prompts on a visual card
• Exit ticket slips and pencils/whiteboards for quick checking
• Timer for station rotation

Assessment

• Teacher observation during guided practice and stations: Does the student use tens-first reasoning?
• Exit ticket review: Identify whether errors are due to tens/ones confusion or sequencing mistakes.
• During whole-class correction, listen for accurate explanations (tens compared first).

Differentiation

• Support for neurodivergent students and EALD:
• Provide a visual rule card: “Tens first, then ones.”
• Use sentence frames: “I know ___ is bigger because it has ___ tens.”
• Offer reduced card sets (3 numbers instead of 4) for quick success.
• Allow pointing to place value blocks and number line marks rather than extended writing.
• Peer assistance:
• Pair students intentionally; assign roles like “Builder” (makes numbers) and “Checker” (checks order on the number line).
• Challenge and extension (advanced learners):
• Provide a set that includes a harder ordering (e.g., numbers with the same tens and varying ones, or include three numbers that require careful comparison).
• Optional extension (teacher adds only if appropriate): order three-digit numbers using place value up to 200–999 range with the same tens/ones idea applied to hundreds.
• Scaffold for students needing extra practice:
• Use a narrower number range (e.g., 10–25) so place value comparisons are simpler.
• Offer additional modelling before stations for students who did not show tens-first reasoning.

Extension (optional)

• Advanced learners order three-digit numbers (e.g., 214, 203, 219) using hundreds-first then tens, then ones, and explain the reasoning in one sentence.