Prefixes and Math

A prefix is defined as a word, letter, or number that comes before another word. This “before” word, or prefix, changes the original meaning in some format.  For example, if you use the prefix centi- before the word meter then you create a centimeter or one-hundredth of a meter. But without the prefix, a meter is a much larger measurement. Math has its own set of prefixes that are important to the operation.  We need to understand how to teach number prefixes to our ESL students in a way that they can connect with so they can understand that number prefixes tell us how many of something, like the meter.

The Beginning

Knowing where to start when teaching any kind of vocabulary is one of the most challenging pieces for teachers. This is even more true when teaching ESL students and especially true when dealing with math vocabulary. So knowing how to teach number prefixes can feel overwhelming. But it doesn’t have to be if we break it down into pieces. I like to start with a word tree. 

Word Trees

Yep, using word trees is one of the best ways to teach number prefixes. We use them all the time with new vocabulary in English class and math should be no different. For this tree, you will want to have the prefixes in one section, some base words in the middle, and then the new words in the last section. Because there are multiple prefixes that can be used with each base word you can have lots of options.

Flashcards for the Middle

Sometimes knowing how to teach number prefixes is going back to the basics, which for me means flashcards. This is what I consider the middle section of my lessons on number prefixes. Students can spread them out and match them up in many different methods. Sometimes I will use flashcards with the whole group. When I do this I will hold the card up and each student will choose a matching card to hold up. I also like to use flashcards for independent practice. The key to this step of the lesson is repetition.

Playing Games for Review

Playing games is one of my favorite ways to review any skill that we are working on. This is no different when I am teaching number prefixes. I have done the work for you in my Math Games. There are several different practice games for number prefixes, just let your students play! The games serve as a great review of everything we just learned with our word tree and flashcards. It is the best end cap for my lesson.

Teaching Number Prefixes

There is no wrong way to teach prefixes. Any exposure that you give your students to the “before” words is excellent exposure. I hope that some of these ideas will help get you started though so that your students can expand their math vocabulary and start to feel confident in their math classes.