Teacher Guide
Week 15
Length: Inches & Centimeters — Teacher Guide
Monday: Measuring in Inches
1
Warm-up: Choose Tool
1.
pencil: ruler, door: measuring tape, book: ruler, waist: measuring tape
2
How to Use a Ruler
1.
Demonstration — line up at 0, read the end mark
3
Estimate First
1.
A=3 in, B=5 in, C=2 in (accept any reasonable estimate)
4
Measure in Inches
1.
1) 4 in, 2) 1 in, 3) 6 in, 4) 3 in
5
Word Problem
1.
2 inches longer (6−4=2)
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Tuesday: Measuring in Centimeters
1
Warm-up: Inches Review
1.
A=2 in, B=5 in
2
Meet the Centimeter
1.
Discussion — cm is smaller than inch
3
Estimate First
1.
A=8 cm, B=12 cm, C=5 cm (accept reasonable estimates)
4
Measure in cm
1.
1) 10 cm, 2) 4 cm, 3) 14 cm, 4) 7 cm
5
Word Problem
1.
14 cm (5+9)
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Wednesday: Inches vs. Centimeters
1
Warm-up
1.
1 inch is longer; centimeters gives the bigger number (smaller unit → more of them)
2
Measure Two Ways
1.
Line A: 2 in ≈ 5 cm; Line B: 4 in ≈ 10 cm
3
Number Talk
1.
Centimeters — the unit is smaller, so you need more of them to cover the same length
2.
Sam forgot the UNIT — '3' could be 3 inches, 3 cm, or 3 feet
4
Best Unit
1.
ant: cm/inches (small), bed: feet/meters (big), paper clip: cm/inches (small), door: feet/meters (big)
5
Estimate Real Objects
1.
Accept reasonable estimates; typical: pencil ≈ 7 in, hand span ≈ 15 cm, spoon ≈ 6 in, shoe ≈ 20 cm
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Thursday: Comparing Lengths
1
Warm-up
1.
A=6 cm, B=11 cm
2
How Much Longer
1.
Pair 1: 9 and 4, 5 cm longer | Pair 2: 13 and 6, 7 cm longer | Pair 3: 10 and 7, 3 cm longer
3
Word Problems
1.
6 inches longer (14−8)
2.
40 cm (25+15)
4
Order by Length
1.
A=5 in, B=2 in, C=4 in; order: B, C, A
5
Create Own
1.
Accept student drawings ≈3 in and ≈5 in with a valid comparing question
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Friday: Review & Self-Check
1
Warm-up
1.
1 inch is LONGER than 1 cm; ant → centimeters (or inches)
2
Estimate First
1.
A=4 inches, B=9 cm (accept reasonable estimates)
3
Measuring Review
1.
1) 3 in, 2) 12 cm, 3) 5 in, 4) 8 cm
4
Word Problems
1.
9 cm (15−6)
2.
19 inches (12+7)
5
Self-Check
1.
Accept student self-assessment and reflection