IB skill practice

Use modular inverses

Find and use modular inverses in congruence equations.

Paper 1, Paper 2 5 marks Difficulty 5

Use modular inverses - modular inverse item

Case A15. Use the residue cycle to calculate the inverse, congruence solution, or modular division value.

Worked practice: result and interpretation

Calculate the requested result first, then choose the interpretation that follows from it.