The four numerical stamps stamp shown below are designed to fill in the three blank squares and complete the equation. Only one digit can be used in each square.
Your task is to make a valid equation using the fewest number of stamps to fill all three blank squares.
Pick the stamps you'll use by checking the boxes below them, and then tap Submit.
UK Version
Here are four numbered stamps.
Stamp the numbers into the blank spaces to complete the equation. Only one digit can fit into each blank space, and you must use the lowest possible number of stamps.
Select the stamps that you need to use, then touch Submit.
Hints
Click a Tab to reveal the Hint.
US Version
Think of all the equations with a one-digit answer that you can make from the four stamps provided.
There aren't that many combinations, so you should be able to figure out the results in no time.
UK Version
Think of all the combinations of the four numbers that you can add together to get a one-digit answer.
There are not many combinations, so you should be able to find the results in no time.
US Version
Using only one, three, five, and seven won't allow you to create a valid equation. This calls for a shift in your thinking. Pay close attention to the shape of each stamp...
UK Version
There is no combination of numbers here that can be added together to produce an answer that is 1, 3, 5 or 7.
Times like this call for a new approach. Pay close attention to the shape of each stamp.
US Version
The key to this puzzle is that you're using stamps. One of the stamps can be used twice in the same square to create a single digit. Picture how you might rotate the stamps, and see if you can figure it out.
UK Version
The key to this puzzle is the fact that you're using stamps.
There's one stamp here that can be stamped into a blank space, rotated and stamped again into the same space to make a new number.
US Version
If you use the three stamp twice in a single blank square, you can make a different number and it only counts as one stamp. Use that to number as the answer to the equation.
Now just figure out what else you need to use and you'll be done. But don't forget that you're trying to use the fewest number of stamps possible.
UK Version
You can create a new number by using the 3 stamp twice. Put this new number on the right side of the equation.
Don't forget to use the lowest possible number of stamps to complete the equation.
Solution
Incorrect
US Version
Too bad!
Be sure to consider all possibilities.
UK Version
Too bad.
If your equation doesn't work out, try thinking about it from a different angle.
Correct
US Version
Correct!
The three and five stamps are all you need! The equation can be solved by making 1 + 7 = 8, but that uses three stamps. You only need two stamps to make 3 + 5 = 8.
UK Version
That's right!
The stamps you need to use are 3 and 5.
The equation works out if you enter 1 + 7 = 8, but if you enter 3 + 5 = 8, you only use two stamps.