What’s the Difference? Contributions of Lexical Ambiguity, Reading Comprehension, and Executive Functions to Math Word Problem Solving in Linguistically Diverse 3rd to 5th Graders

ABSTRACT Purpose Math word problem solving, a form of reading comprehension, is complicated by mathematical lexical ambiguity (e.g., the word difference can mean dissimilarity in everyday discourse but the answer in a subtraction problem in math). This study examined the role of mathematical lexical ambiguity in math word problem solving. Method Lexically ambiguous math word knowledge, reading comprehension, vocabulary breadth, executive function (EF) skills, and math word problem solving were assessed in 521 3rd- to 5th-grade emergent bilingual (EB) and English monolingual (EM) students. Results Students knew fewer math than common meanings of lexically ambiguous math words, and EBs knew fewer meanings than EMs. Multi-group path analysis indicated reading comprehension and lexically ambiguous math word knowledge contributed directly to math word problem solving and partially mediated the influence of EFs on math word problem solving. Conclusion Consistent with the language function hypothesis, language skills supported math word problem solving directly and mediated the influence of EF skills on math word problem performance for both EBs and EMs alike. Our findings move the field forward by revealing a specific mechanism by which EF skills contribute to a particular aspect of content area reading comprehension.