Order of operations

Pause the video and calculate this mentally: 2 + 3 * 2. Did you get 10? If so, you need to learn the order of operations. This tells you the order in which you calculate the different parts of a mathematical expression. If you take the parts in the order they come, you first get 2 + 3 = 5, and then * 2 which is 10.

But if you do multiplication first, you get 3 * 2 = 6, and then 2 + 6 you got which equals eight, and eight is the correct answer. Multiplication and division always precedes addition and subtraction. If we include an exponential expression, it has even higher priority than multiplication and division. 2 + 3 * 2^3, start with the power. 2^3, 8, then the multiplication, 24, and finally the addition, 26.

Exponential expressions come before multiplication and division. But sometimes you need to calculate in a different order. Leon and Lina have two oranges and three bananas each, how many fruits do they have together? (2 + 3) * 2. Here we want to add two and three first to see how many fruits each of them have. And then multiply by the number of people, two.

Therefore, we place parenthesis around the parts we want to calculate first. Now you add parenthesis, five,  and this time the answer is 10. They have 10 fruits altogether, not eight, which you would have found if you would have calculated without the parenthesis. So here it is, the order of operations which you need to know by heart. Parenthesis first, powers next, then multiplication and division, and then finally addition and subtraction.