As part of the release plan for the Texas Assessment of Knowledge and Skills (TAKS), the Texas Education Agency (TEA) releases the primary form of TAKS tests every three years. In non-release years, TEA releases a set of representative items that have been field-tested but are no longer eligible for inclusion on an actual test.
The released set of representative TAKS items for every grade and subject assessed—both in English and in Spanish—includes an answer key, which provides the objective, the TEKS student expectation, and the correct answer for each item.
Here are the released items for 2010:

Texas Math and Science Diagnostic System (TMSDS)

Region 9 Released TAKS Questions by TEKS
Region 9 Released TAKS Questions by Objective

Online Versions of TAKS Study Guides from TEA -

Open Ended TAKS Problems -

Math Counts -

Free Test Prep Questions from Princeton Review -

Mathematics Benchmarks, K-12:

TEKS Support Resources -

Test and Worksheet Generators for Math Teachers -