P2A · Applied mathematics · MEAS.LENGTH.MASS.CAPACITY

Measure length, mass and capacity

Measure length, mass and capacity

Practice this skill
Intuition

Understand first, compress later.

Mathematical models translate real situations into quantities, relationships and assumptions.

Switch representations
Measuring with a ruler6.4 cm = 64 mm
012345678cmthe ruler's edge — there is no zero hereline up with 0 and read off at the other end
the object being measuredzero mark — the measurement starts hereedge of the ruler — do not read from it
The object's left end sits exactly on zero, not at the edge of the ruler — that is not where the scale begins. Ten millimetre marks lie between two centimetre marks; the reading is 6.4 cm = 64 mm. A length is always the distance between two marks, never a single number on the scale.
Formal view

You can measure length, mass and capacity when you can recognise the underlying objects, select valid rules and check each step for equivalence or logical implication.

Why does it work?

This skill sits on a prerequisite network. If a step is unstable, repair the missing prerequisite instead of merely doing more items of the same type.