Edexcel 4MA1 Foundation papers are calculator-based, so the real skill being tested is not arithmetic — it's turning a sentence into the right calculation. Keywords give this away: "total", "sum" or "altogether" signal addition; "left over", "difference" or "how much more" signal subtraction; "cost of several items" signals multiplication; "shared between" or "cost per item" signals division. Many questions need two of these in sequence, so read the whole problem before writing anything down.

Break it into a clear chain of calculations, writing down each intermediate value.

Example: Janine has 2 litres of squash and fills as many 300 ml cups as possible. How much is left over?

1. Convert to consistent units: $2\text{ litres} = 2000\text{ ml}$.
2. "As many as possible" means divide and ignore the remainder: $2000 \div 300 = 6$ remainder $200$, so 6 full cups.
3. Squash used: $6 \times 300 = 1800\text{ ml}$.
4. Squash left: $2000 - 1800 = 200\text{ ml}$.

Brackets, then Indices, then Division/Multiplication (left to right), then Addition/Subtraction (left to right). Division and multiplication share equal priority — they are not done in alphabetical order, just left to right as they appear.

Picture a number line. "Risen by" or "increased by" means move right (add); "fallen by" or "decreased by" means move left (subtract a positive amount).

Example: Temperature at midnight is $-7°C$. It rises $5°C$ by midday.

A train is scheduled at 16:15 but arrives at 15:50. A second, later train then takes 2 hours 40 minutes to reach its destination, leaving 35 minutes after the first train arrives. At what time does the second train arrive?

1. First train is early by: from 15:50 to 16:00 is 10 minutes, then 16:00 to 16:15 is 15 minutes, total $10+15=25$ minutes early.
2. Second train leaves $35$ minutes after $15:50$: $15:50 + 0:35 = 16:25$.
3. Add the journey time: $16:25 + 2:40 = 19:05$.

Answer: the second train arrives at 19:05.