Question

which number is the best estimate for 45.1 × 1.5? 25 40 70 90

Explanation:

Step1: Round the numbers

Round \( 45.1 \) to \( 45 \) (since \( 45.1 \) is close to \( 45 \)) and keep \( 1.5 \) as it is.

Step2: Estimate the product

Calculate the estimated product: \( 45\times1.5 \). We know that \( 45\times1 = 45 \) and \( 45\times0.5=22.5 \), so \( 45\times1.5 = 45 + 22.5=67.5 \). Among the given options (25, 40, 70, 90), 70 is the closest to 67.5. Also, if we round \( 45.1 \) to \( 50 \) (a common estimation), then \( 50\times1.5 = 75 \), and 70 is still the closest among the options.

Answer:

70