Grade 10 — Mathematics 10C › C10U01 Measurement Systems & Conversions

Grade 10 › C10U01 Measurement Systems & Conversions › L1
GRADE 10 · ALBERTAOUTCOME AB-MAT10C-M1

L1 · The SI System: Linear Measurement and Referents

Learning goal

“I can choose the right SI unit (mm, cm, m, km) for a measurement, name a personal referent for each unit and explain my choice, read a measurement from a ruler, and move between SI units by powers of ten.”

Referent — a familiar object or body part whose size you know, used to judge or estimate an unknown length (e.g., your fingernail's width is about 1 cm).
SI system (metric) — the measurement system built on powers of ten: millimetre, centimetre, metre, kilometre.
Millimetre (mm) — one thousandth of a metre; about the thickness of a dime.
Kilometre (km) — 1000 metres; about 2.5 laps of a standard 400 m running track.
Worked example

Match each object to a unit and a referent: (a) thickness of a phone -> mm (one phone is about 8 mm, and mm keeps the number whole). (b) length of a classroom -> m (about 9 doorknob heights, about 9 m). (c) distance from school to the next town -> km (about 30 track laps). Say it plainly: pick the unit that makes the number land roughly between 1 and 1000, and anchor it to something your body knows.

Check yourself — explain it

Why is 1 cm a better unit than 1 mm for the length of a pencil?

Paired problem — example still visible

Length of a bed -> unit and referent? -> m; about two doorknob heights, about 2 m

Faded completion — last step is yours

"Height of a cereal box -> cm; referent: about ___ fingernail widths" -> about 30

Ready to practise?

10 scored questions with a 3-rung hint ladder. Mastery needs 8/10 plus both gate questions.

Start practice →Take the unit quiz