Missing Numbers
How to create
Create these puzzles by taking a simple addition or subtraction equation and leaving out some of the digits. If you accidentally leave out too many numbers, that can open up a discussion of what all the possible solutions are – for example, if you start with 2 + 5 = 7 and leave out the first and third numbers, there are many solutions to ? + 5 = ?
Example
The following two problems are turned into Missing Number puzzles by leaving out a couple digits in each one.
Letter substition puzzles
These missing number puzzles form a very understandable stepping stone to using simple variables. After getting comfortable with these puzzles, your child will be ready to do some Letter Substitution puzzles that are described later in this Stage.
Helping your child
Puzzles are meant to be challenging and to take time, so please don’t ruin the fun by telling your child how to do them. These puzzles are chosen so that you can create them easily and then have fun solving them together.
If your child gets stuck on a puzzle, you have several options. You can, of course, give very small hints, if you can think of things that won’t give away the puzzle. You can suggest looking at smaller or simpler versions of the puzzle. Encourage your child to be bold in their ideas, even if sometimes they lead to dead ends. We all learn a lot from our mistakes and dead ends! Let your child know that it is perfectly okay not to solve a puzzle on the first (or second or third) try, and that useful ideas may occur to them if they leave the puzzle alone for a day or two.
These puzzles are meant to be fun and to teach problem solving. One of the greatest mathematical pleasures is that AHA moment, after many false starts and much wrestling with a problem, when the answer is finally discovered – be sure to let your child experience that feeling of discovery as many times as you can!