Accuracy and Precision
Aligned to N-Q.A.3 — Common Core State Standards for Mathematics.
What this lesson teaches
Report answers only as precisely as your measurements allow — extra decimals suggest accuracy you do not actually have. Match the significant figures of your answer to your least precise measurement.
Worked example
A rectangle measures 4.2 cm by 3.15 cm. The product is 13.23 cm^2, but since 4.2 has only 2 significant figures, report the area as 13 cm^2.
Practice questions
- A board is measured as 2.5 m. Why is writing its length as 2.500 m misleading?
- Round 47.86 kg to 2 significant figures.
- You measure a table as 1.2 m by 0.85 m. State the area to an appropriate precision.
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
Exactitud y Precisión
Reporta las respuestas solo con la precisión que permiten tus medidas: los decimales de más sugieren una exactitud que en realidad no tienes. Ajusta las cifras significativas de tu respuesta a tu medida menos precisa.
Ejemplo: Un rectángulo mide 4.2 cm por 3.15 cm. El producto es 13.23 cm^2, pero como 4.2 tiene solo 2 cifras significativas, reporta el área como 13 cm^2.
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