There are four versions of the binary number trick below. To perform the trick, print out the binary number cards double-sided and cut them out along the dotted lines. Then, have someone think of a number between one and the highest number you see on the cards (1-7 or 1-15 or 1-31 or 1-63). Then, ask them to say yes or no to indicate if their number shows up on each card. For the cards they say yes to, add up the numbers in the top right corner and mathemagically you will have their number. For the 1-7 and 1-15 versions below, young children can set the cards someone says yes to on the side and then count of all the dots on the back to get the number someone is thinking about.
A cool trick with the 1-31 cards is to ask someone to think of the number for the day they were born and then figure it out mathemagically to impress them.
At the end there is also a PowerPoint version of the 1-31 cards which can be included in presentations to wow large crowds of people!
Early Childhood Version 1-7 (Dots on the back for counting)
Early Childhood Version 1-15 (Dots on the back for counting)
Advanced Version 1-31 – adding the top left numbers together for “yes” cards
Early Childhood Version 1-31 (Dots on the back) – counting and skip counting by 5’s instead of adding numbers
Advanced Version1-63 – adding the top left numbers together for “yes” cards
Early Childhood Version 1-63 (Dots on the back) – counting and skip counting by 5’s instead of adding numbers
PowerPoint Version 1-31
Binary Math “Magic” Lesson
Binary Math “Magic” Build Your Own Trick Cards
It is not obvious to me which should come first, finding the patterns on the cards in the previous lesson or building your own trick cards. I look forward to hearing feedback from teachers who have tried them to find out.
The video below is referenced in the lesson plan above and is one of the best at explaining binary numbers in a concise, accurate way.