Be able to write programs that use arithmetic operators (addition,…

The idea

This criterion requires you to write working program code, not merely name operators. In a language such as Python, addition combines values (total = price + tax), subtraction finds a difference (change = paid - cost), multiplication scales (area = width * height) and division produces a quotient (mean = total / count). Modulus returns the remainder (remainder = value % 7), which is useful for testing divisibility or wrapping values. Integer division discards the fractional part (whole = total // count), giving how many whole times one number fits into another. Exponentiation raises a base to a power (area = side ** 2 for a square, volume = side ** 3 for a cube). Choose the operator that matches the required output, apply it to the correct operands, and check the result with a test value.

What earns the marks

• Selects the correct arithmetic operator for a stated purpose, for example addition to combine two quantities or multiplication to scale a value.
• Writes a complete expression in which every operator has both operands, such as total = price + tax or area = side ** 2.
• Distinguishes modulus from integer division: modulus yields the remainder, while integer division yields the number of whole times one value fits into another.
• Uses exponentiation for powers, for example side ** 2 for a square's area and side ** 3 for a cube's volume, rather than repeated multiplication written incorrectly.
• Applies the correct order of operations or uses brackets so that a compound expression evaluates as intended.
• Tests the program with sample inputs and confirms the output matches a hand-calculated result.

Common mistakes and how to put them right

• Confusing modulus with integer division.

  Put it right: Modulus returns the remainder, so 17 % 5 gives 2, while integer division 17 // 5 gives 3.

• Writing an expression in which an operator has only one operand, which is a syntax error.

  Put it right: Every operator needs a value on each side, so write the full expression with both operands present.

• Assuming ordinary division always produces a whole number.

  Put it right: Ordinary division can produce a fractional result, so use integer division when a whole-number quotient is required.

• Using exponentiation when simple multiplication is intended, or vice versa.

  Put it right: Match the operator to the mathematical meaning, using exponentiation only for raising a base to a power.

Exam tips

• Read the question's required output first, then choose the operator whose result matches that output rather than the operator that looks familiar.
• Trace a short expression with small numbers by hand before selecting an answer, so the predicted result can be compared with each option.
• Check each candidate expression for completeness: every operator must have a value on both its left and its right.
• When two options differ only in one operator, evaluate both with the same sample numbers and compare the results.