3.12

## Weizmann Institute of Science

Skip to 0 minutes and 0 secondsSo, it's time to take a look at operator crossword puzzles. This is an operator crossword puzzle and it's a puzzle where there are digits inside or numbers inside and the numbers, when an operator is placed between any two numbers or any row gives the result written outside the rows and outside the columns so all we need to do is fill in the missing squares, the blanks with operators.

Skip to 0 minutes and 33 secondsIn this simple operator crossword, you need to just plug in plus, minus, multiplication and division and try and get the numbers in the rows and in the columns and by the way, this operator crossword doesn't have a unique solution, there can be many solutions, you can see this already in the top row - to get 18 you can either multiply 9 by 6 to get, six nines are 54 and divide that by 3 to get 18, or you can just write two plusses here, 9 plus 6 is 15, plus 3 is 18. So, we've done the first row. The second row - 5 something 2 something 4 gives minus 1

Skip to 1 minute and 19 secondsand this is also pretty easy: five minus 2 is 3 minus 4 is minus 1. And we need to get 2 from 1, 8 and 7 so 1 plus 8 is 9, minus 7 gives us 2. You have to make sure by the way that the operators operate in order. Multiplication and division before addition and subtraction. So, let's try now with the columns and get from 9,5 and 1, 13, and again this is pretty simple - 9+5 is 14, -1 is 13.

Skip to 1 minute and 59 secondsand in the middle, 6,2 and 8 we need to find an operation that gives us 11, notice that here, all the numbers are even, so we're going to somehow need to get from two odd numbers an even number so that the sum will be, Err.. from two even numbers an odd number, so that the sum will be odd and the way to do this is by division. That's the only way, by the way, you can do this if you're given just even numbers, so, 6 divided by 2 is 3, and 3 plus 8 is 11, and the last one, 3,4 and 7 have to give us 5,

Skip to 2 minutes and 43 secondsand this can be done in the following way: three fours are twelve, minus seven is five.

# Operator crosswords

Operator crossword puzzles are real fun!
Here is a great site where you can try to solve some operator crosswords of the first type and here are some operator puzzles of the second type. Have fun!