Teachers of ESL students in content areas know how important it is to close the gap between English and content mastery. To that end, language objectives are essential. Read more about this topic in Language Objectives: The Key to Effective Content Area Instruction for English Learners at http://www.colorincolorado.org/article/language-objectives-key-effective-content-area-instruction-english-learners
Don’t forget to frontload math language concepts, words, and all needed info to your students before the lessons and make sure to add language objectives to your lesson plan. Find the great resources for math lessons in English language here at https://ket.pbslearningmedia.org/collection/peg-cat/?utm_source=PBSEDU&utm_medium=email&utm_campaign=days_2017#.WhRbF7Q-fUI
A good reading for teachers who are interested in content English in How to make math a key part of your ELL curriculum at https://www.eschoolnews.com/2017/09/25/make-math-key-part-ell-curriculum/
Super interesting research findings in Bilingual People’s Brains Process Arithmetic in a Quirky Way, Study Shows at https://www.sciencealert.com/bilinguals-use-different-parts-of-their-brain-to-solve-arithmetic-in-each-language
Always an important question. Find the publication here at http://exclusive.multibriefs.com/content/using-content-materials-for-esl-instruction/education
EVERY teacher is an ESL teacher! Therefore, pay attention to teaching language alongside with content. See some examples here is videos of real teachers.