Measurement and Data (Grade 3)
Measurement and Data in Grade 3 covers telling time to the nearest minute and finding elapsed time, measuring mass and liquid volume, reading scaled graphs and line plots, and understanding area and perimeter. The NYS test mixes straightforward measurement with multi-step problems, especially where area and perimeter are compared.
Time, mass, and volume
- Read time to the nearest minute, then find elapsed time by counting forward in friendly jumps.
- Mass is measured in grams and kilograms; liquid volume in liters. A kilogram is 1,000 grams.
Graphs and line plots
- On a scaled bar or picture graph, check the key: one square or symbol may stand for 2, 5, or 10.
- A line plot uses an X above each measured value. Measurements may be to the nearest half or quarter inch.
Area and perimeter
- Area is the number of unit squares covering a shape. For a rectangle, area = length x width.
- Perimeter is the distance around a shape: add all side lengths.
- The distributive property connects area to multiplication: 7 x 4 = 5 x 4 + 2 x 4.
- Rectangles can have the same perimeter but different areas, or the same area but different perimeters.
Worked example
A rectangle is 7 cm long and 4 cm wide. Area: 7 x 4 = 28 square centimeters, because 7 rows of 4 unit squares cover it. Perimeter: 7 + 4 + 7 + 4 = 22 centimeters, because perimeter measures the boundary, not the inside.
Traps
Confusing area (inside, square units) with perimeter (around, linear units). Ignoring the graph key and counting symbols as single items. Counting X marks on a line plot without reading the value beneath them. Losing track of the hour when elapsed time crosses it.