# Math Mind Magic

Every student can be a magician after this lesson in mentally adding and subtracting by 10. No previous magic training required!
Need extra help for EL students? Try the Add and Subtract with Dimes pre-lesson.
##### View aligned standards
Need extra help for EL students? Try the Add and Subtract with Dimes pre-lesson.

#### Learning Objectives

Students will be able to mentally find 10 more or 10 less than a given two-digit number without counting.

The adjustment to the whole group lesson is a modification to differentiate for children who are English learners.

#### Introduction

(10 minutes)
• Call students together around the hundreds chart.
• If you have wardrobe items, wear them.
• Tell your students that today they are going to be math magicians. In order to perform this magic trick, inform them that they will need some props.
• Hand out lots of index cards to each student.
• Instruct your students to write a number between 10-90 on one side of each card. On the other side of the cards, have the students write a plus sign with the number 10 and a minus sign with the number 10.
• Demonstrate this process for students. Explain that they can count or use the hundreds chart to figure out what number is 10 greater (more) or 10 less (smaller).

Beginning

• Put a sticky note on the numbers 10 and 90 on a number line. Gesture at the numbers in the middle as you say, "between."
• Create an anchor chart for reference. Write, "+ plus sign more" and "- minus sign less".
• Show students how to form a plus sign with both arms as they repeat, "plus sign." Next, gesture with hands far apart and have them repeat in a loud voice, "more."
• Tell them to gesture with one arm parallel to the ground as they repeat, "minus sign," and then gesture with hands close together as they repeat in a soft voice, "less."
• Add further math symbols to the chart as they are introduced in subsequent lessons.

Intermediate

• Invite students to share ideas for figuring out what number is 10 greater or 10 less than a given number. Record student ideas on the board before suggesting that they count on or use the hundreds chart (if students do not suggest these strategies).