This study investigates whether word problems and mathematically expressed items can be used interchangeably regardless of their linguistic complexities. A sample of sixth grade students was given two forms of a mathematics assessment. The first form included mathematics items with mathematical terms, expressions, and equations whereas the second form included the same items as word problems. Explanatory item response modeling was used for examining the impact of item type and gender on difficulty levels of items and test scores. The results showed that word problems were easier than mathematically expressed items. Gender and its interaction with the linguistic complexity of mathematics items did not seem to have any impact on student performance on the test.