Measurement | NZ Maths

GM4-1: Use appropriate scales, devices, and metric units for length, area, volume and capacity, weight (mass), temperature, angle, and time.

This means students will work with the commonly used units of the metric system and measurement devices for:

GM3-2: Find areas of rectangles and volumes of cuboids by applying multiplication.

This means students will begin by measuring the areas of rectangles and other shapes using square units. This is because square units of the same size tessellate, that is join together with no laps or overlaps. That means that the measurement is consistent whereas the use of a non-tessellating unit would give variable results due to gaps and overlaps. Similarly, volume is measured in cubes of the same size. At Level Three students should apply whole number multiplication to make the process of counting squares or cubes more efficient.

GM3-1: Use linear scales and whole numbers of metric units for length, area, volume and capacity, weight (mass), angle, temperature, and time.

This means students will recognise that length, area, volume and capacity, weight, angle, and temperature are the characteristics (attributes) of objects people most commonly measure in everyday life. Time is a special attribute since it is not tangibly attached to physical objects. Measurement involves quantifying an attribute using units. Units of measure have characteristics including being a part of the attribute they measure and uniformity (same size). When measuring, the units need to fill a length, space, time etc., with no gaps or overlaps (this is known as tiling).

GM2-2: Partition and/or combine like measures and communicate them, using numbers and units.

This means students will perform and communicate calculations involving like measures. Like measures involve the same units for the same attribute. This allows the result of joining or separating units to be anticipated using additive number strategies. For example, a box has a volume of 36 cubes. If a 3 by 4 cube layer is put in the empty box then there will be space for 36 – 12 = 24 more cubes. At Level Two students should be able to use numbers and common symbols to communicate measurement results, for example my lunchbox holds 60 cubes. I took 13 minutes to walk home.

GM2-1: Create and use appropriate units and devices to measure length, area, volume and capacity, weight (mass), turn (angle), temperature, and time.

This means students will recognise that the attributes length, area, volume and capacity, and weight can be measured. At Level Two students are expected to recognise that measurement units are countable and therefore able to be partitioned and recombined in the same way as other units of one. For example, if an 8 unit length is cut from a 14 unit long strip the remainder will measure 6 units. Units of measure have other characteristics including being a part of the attribute they measure and uniformity (same size).

GM1-1: Order and compare objects or events by length, area, volume and capacity, weight (mass), turn (angle), temperature, and time by direct comparison and/or counting whole numbers of units.

This means students will go through a stage of using direct comparison to establish the relative length, area, volume, weight and temperature of objects. This means that the objects are brought together physically. Through experiences using direct comparison techniques students will come to appreciate the need for units of measure so that objects can be compared without bringing them together. Units have the attribute being measured, have to be the same size and are combined and counted. For example handspans can be used to compare the length of a table and the height of a door.