Enrichment activities for fourth-grade mathematics are presented. Some of the activities reinforce principles taught in the regular program; others introduce new concepts to challenge students. The activities are divided into the following categories: number pictures; multiplying or dividing by 10, 100, or 1000; tic-tac-toe word problems; map coloring; number tricks; logic puzzles; crossnumber puzzles; letters make words and words make cents (making words out of letters with differing point values); suppressed digits; Victorian arithmetic; graphing; geometric shapes; spatial perception; word problems (advertising puzzles); finding the square root of a number; and number sense (patterns in multiplication and division). Answers to the puzzles and other activities are appended. (DC)