Rounding to significant figures and applying precision to calculations

Task goals

• Count how many significant figures are in a number, including numbers with leading, trailing, or placeholder zeros.
• Round a number to a stated number of significant figures.
• Convert a number written in scientific notation to an ordinary number, and an ordinary number to scientific notation, to a stated number of significant figures.
• Carry out a calculation (addition, subtraction, multiplication, or division), including with numbers in scientific notation, and round the result to a stated number of significant figures.
• Compare two or three decimal values with different numbers of trailing zeros and identify which is written to the greater precision.
• Apply significant-figure rounding to a real-world calculation such as an area, speed, or density, giving the answer to a stated number of significant figures.