A calculator is a useful tool for handling calculations accurately and efficiently, but it must be used with a clear understanding of how it processes operations. Correct key entry, sensible use of brackets, and awareness of calculator functions are essential for avoiding errors.

Calculators follow the order of operations automatically. This means multiplication and division are carried out before addition and subtraction unless brackets are used.

$$
3 + 4 \times 5 = 23
$$

If the addition must be done first, brackets are required.

$$
(3 + 4) \times 5 = 35
$$

Brackets should always be used when the order matters, especially in long calculations.

Calculators can be used for addition, subtraction, multiplication, and division with both whole numbers and decimals. Care must be taken to enter decimal points correctly.

$$
78.4 - 12.96 = 65.44
$$

$$
45 \div 8 = 5.625
$$

To calculate squares, cubes, and other powers, use the square key or the power key.

$$
7^2 = 49
$$

$$
3^3 = 27
$$

$$
2^5 = 32
$$

To calculate square roots and cube roots, use the root function or powers.

$$
\sqrt{81} = 9
$$

$$
27^{\frac{1}{3}} = 3
$$

Brackets are essential when entering expressions involving several steps. Missing brackets can completely change the result.

$$
(12 + 6) \div (3 + 3) = 3
$$

Calculators also include other useful functions, such as percentage calculations and powers of ten for standard form. Understanding what these buttons do helps you choose efficient methods.

$$
35\% = 0.35
$$

Always estimate before and after using a calculator. This helps you check that the result is reasonable and that no keys were pressed incorrectly.