Rounding & Estimation (Cambridge (CIE) IGCSE International Maths: Core): Exam Questions

By writing each number correct to 1 significant figure, estimate the value of

$\frac{37.8\times 13.2}{28.5+22.1}$

You must show all your working.

By rounding each number correct to 1 significant figure, estimate the value of

$\frac{71\times 32.4}{4.8^2}$

You must show all your working.

Calculate $\sqrt[3]{40}$

Give your answer correct to 4 decimal places

By rounding each number correct to 1 significant figure, show that an estimate for this calculation is 20.

$\frac{9.78+31.562}{0.381\times 5.09}$

Write 0.047883 correct to 2 significant figures.

Write 6.8167 correct to 3 significant figures.

$T=\frac{49.2-9.59}{4.085\times 2.35}$

By writing each number correct to 1 significant figure, work out an estimate for $T$.
You must show all your working.   

By rounding each number correct to 1 significant figure, estimate the value of $\sqrt{\frac{90006}{10.{01}^2}}$

You must show all your working.

$p=\frac{1.6+9.6^2}{5.9-4.3}$

By writing each number correct to 1 significant figure, work out an estimate for $p$.
You must show all your working.

Write 0.046875 correct to 2 significant figures.

Without using a calculator, estimate, by rounding each number correct to 1 significant figure,

$\frac{\sqrt{104.3}}{8.72-7.389}$

You must show all your working.