Scholastic is one of my favorite sites of wonderful activities for students and teachers. One section that has recently been updated is Math Maven.
The Math Maven is always finding herself in the middle of a fun new mystery — and she counts on her "super sleuths" to crack the case. Each mystery focuses on a particular area of math reasoning and computation and requires students to use creative thinking and sharp math skills to help her find the solution.
The Math Maven activities are leveled easy, medium, and difficult and cover the following areas: logical reasoning, whole number operations, fractions & ratios, money & decimals, patterns & missing numbers, measurement & time, combinations & probability, and geometry & spatial reasoning.
Each Math Maven mystery has audio of the story as well as a printable PDF available and is interactive whiteboard ready. These Math Maven mysteries would be great for individual work on your student computers.