Arithmetic sequences and missing parameters

Practise arithmetic sequences, common differences and missing parameters. Learn to recover a rule from nonconsecutive terms, distinguish the first term from an intercept, insert equally spaced values and decide whether a requested value actually occurs at an integer index. Problems also connect two sequences and examine the structure of subsequences.

Single-select and multiselect questions progress from direct evaluation to parameter reconstruction and justification. Detailed explanations show how many index gaps separate two observations, how to preserve the starting convention and how to check a result in the original terms. Use exact arithmetic and scratch paper. The focus is on individual terms and additive structure; cumulative totals are developed in the following arithmetic-series set.