Grade 2: Measurement

Warm up with a quick recall on the board. Measure real objects with informal units first, then standard units, lining up from zero and keeping units consistent. Estimate before measuring.

Metric measurement uses units that scale by powers of ten, so converting between them means multiplying or dividing by 10, 100 or 1000. Length runs mm, cm, m, km; mass runs g, kg; capacity runs mL, L. Knowing the size of each unit and which way to multiply is the whole skill. Model the method clearly, thinking aloud:

• Fix the size of each unit with a real reference: a centimetre is about a fingernail's width, a metre is a big stride, a kilogram is a bag of sugar.
• Learn the key relationships: 10 mm in a cm, 100 cm in a m, 1000 m in a km, 1000 g in a kg, 1000 mL in a L.
• Decide the direction: going to a smaller unit multiplies (the number gets bigger), going to a larger unit divides (the number gets smaller).
• Check the answer is sensible: 3 m as centimetres should be a bigger number (300 cm), not a smaller one.
• Move to two-step problems and adding mixed units once single conversions are secure.

Work this through step by step on the board, then have the class talk you through a second one.

• Convert 3.5 m to centimetres:
• 1 m = 100 cm
• a smaller unit, so multiply
• 3.5 x 100 = 350 cm

Do the first few questions of the practice worksheet together, one child explaining each step. Check for understanding before releasing the class to work alone.

Students complete the worksheet independently. Hand out the three difficulty levels below so every child works at the right stretch.

Circulate and look for these, they are the usual sticking points:

• Multiplying when you should divide, or the reverse, so the answer is the wrong size.
• Using the wrong relationship (there are 100 cm in a metre, not 10).
• Moving the decimal point the wrong number of places.
• Forgetting to write the new unit on the answer.
• Not starting at zero on the ruler, leaving gaps or overlaps with units, and mixing units in one measurement.

Pull the class back together. Ask one child to explain measurement in their own words, pose a single check question everyone answers on a mini whiteboard, and name what you will build on next lesson.

Use the independent worksheet as the evidence. A child who can complete it accurately and explain one answer has met the objective; anyone who cannot needs the easier level and a short reteach next session.