JAMB Mathematics 2015 Paper

Concept:Squaring a decimal means multiplying the number by itself. Significant figures are counted starting from the first non-zero digit.Explanation:Compute the square: $0.09^2 = 0.09 \times 0.09$.This equals $0.0081$.For 4 significant figures, begin counting from the non-zero digit 8.Count the digits: $8$, $1$, $0$, $0$.So write two extra zeros after $0.0081$ to show four significant figures: $0.008100$.In standard form, this is $8.100 \times 10^{-3}$.Numerically, this is the same as option C, $0.0081$.Answer:Option C: $0.0081$ (correctly written as $0.008100$ to 4 significant figures).