Estimation：练习题

Work out an estimate for the value of \(52.3 \times 18.7\) by rounding each number to \(1\) significant figure.

By rounding each number to one significant figure, estimate the value of $$\frac{89.7 \times 0.21}{1.96}$$

Write the number \(0.0034762\) correct to \(2\) significant figures.

Work out an estimate for the value of \(\frac{\sqrt{103.4} + 19.82}{0.485}\) by rounding each number correct to \(1\) significant figure.

Write the number \(12.9854\) correct to \(2\) decimal places.

Write the number \( 48721 \) correct to 1 significant figure.

By writing each number correct to 1 significant figure, estimate the value of \( \frac{79.5 \times 4.12}{0.198} \).

By writing each number correct to 1 significant figure, estimate the value of the expression:
\[K = \frac{(78.6 \times 495)^2}{\sqrt{0.0000091} \times 20.3}\]
Give your estimated answer in standard form correct to 1 significant figure.

A large rectangular container has a base measuring \( 18.7 \text{ cm} \) by \( 11.2 \text{ cm} \) and a height of \( 9.6 \text{ cm} \).

(a) By rounding each dimension to the nearest 10, estimate the volume of the container.

(b) The container is being filled with water from a tap at a rate of \( 38.5 \text{ cm}^3 \) per second. By rounding the rate to 1 significant figure and using your estimate from part (a), estimate the time taken to fill the container. Give your answer to the nearest second.

(c) Calculate the actual volume of the container and find the difference between the actual volume and your estimate in part (a).