3.1

## Weizmann Institute of Science

Skip to 0 minutes and 0 secondsMath is all about numbers, at least that's what most people think. When we look at an exercise, like 1+1=2, we are usually interested only in the numbers. We usually take the math signs, like the "+" sign, for granted! This week, however, we’ll focus on the various operations that can be done with numbers rather than the numbers themselves. These operations are called operators. An operator describes an action performed on numbers or on other elements, like figures or even words and sentences.

Skip to 0 minutes and 40 secondsThe most well-known operators are the mathematical operators: addition, subtraction, multiplication and division that operate on numbers. The text operator “concatenate” - joining two operands operates on text. A concatenate B equals AB. The symmetry operators, rotate, flip etc. operate on shapes. This week we’ll take a look at operator puzzles. We will focus on two kinds of puzzles. The first genre is puzzles where expressions are given without the operator and your job is to guess the correct operator. For example, here are three expressions. In all three, the same operator, denoted by a question mark, and we have to try and guess what this operator is. 34 something 12 is 46, 1 something 43 equals 44, minus 7 something 7 equals zero.

Skip to 2 minutes and 5 secondsThis is easy - it is of course addition. 34 + 12 = 46, 1 +43 = 44 and -7 + 7 =0. The second kind of puzzles is operator crosswords like this. Towards the end of the week we’ll take a peek at secret codes and we’ll see the connection between them and operators. Have a good week!

# Introduction to operators

This week we’ll move away from number symbologies and take a look at operators and operator puzzles. An operator describes an action performed on numbers or on other elements, like figures or even words and sentences. Examples of some well-known operators include: addition, subtraction, multiplication, division, and more.

## Discussion

Suggest some operators in the comments below!