Civil Service Professional
Numerical Ability
Accuracy begins before calculation: translate the situation, estimate the result, choose an efficient operation, and verify that the final answer makes sense.
Core operations
Refresh place value, signed numbers, fractions, decimals, percentages, ratios, averages, and order of operations. Keep units visible throughout a solution. When converting percentages, write the base explicitly so you do not calculate the correct percentage of the wrong quantity.
Number sequences
Test simple relationships first: constant differences, constant ratios, alternating operations, two interleaved sequences, and changes in the differences. Avoid forcing an elaborate pattern when a simpler one explains every transition.
Worked example
For 4, 7, 13, 22, 34, the differences are 3, 6, 9, and 12. The next difference is 15, so the next term is 49.
Word-problem translation
- Name the unknown and its unit.
- List only the facts needed to determine it.
- Write a relationship before entering numbers.
- Estimate a reasonable range.
- Calculate and test the result against the question.
Common structures include rate × time = distance, part = percent × whole, proportional sharing, weighted average, work rates, and simple budget or inventory changes.