Number Sequence & Logic Test Practice: Differences, Ratios, Interleaved Series, Letter Codes and Grid Puzzles

What you'll build

What you will be able to do

Each lab ends with a concrete result that you build yourself and the checker confirms, cell by cell.

• Find the constant difference of three series, continue them, jump straight to the 25th term of a series and fill a gap in the middle of another.
• Build a difference-of-differences table for a series, read its constant second difference and use it to continue a rising and a falling series.
• Find constant ratios, continue a series without rounding, and work out the multiplier and the added number of a mixed rule like × 2 + 1.
• Split a series into its odd and even positions with MOD, continue the right sub-series, jump to the 12th term and continue a series where two operations take turns.
• Recognise squares, cubes minus one, Fibonacci-type sums and primes, and let formulas continue each one – the primes from a given list.
• Turn letters into alphabet positions with a lookup table, find the step of a letter series, continue it – also past Z – add up a code word and shift a letter with MOD 26.
• Find the rule that every complete row or column follows, use it for the missing cell in three grids and check with one formula that the rule holds across all rows.
• Score a timed practice run of ten mixed questions, work out the score and the average time on wrong answers, and highlight every question that took longer than the target time.