What could you divide and then multiply by to go from the first number to the second?
Answers
Answer:
Operations
"Operations" mean things like add, subtract, multiply, divide, squaring, etc. If it isn't a number it is probably an operation.
But, when you see something like ...
7 + (6 × 52 + 3)
... what part should you calculate first?
Start at the left and go to the right?
Or go from right to left?
Warning: Calculate them in the wrong order, and you can get a wrong answer !
So, long ago people agreed to follow rules when doing calculations, and they are:
Order of Operations
Do things in Parentheses First
yes 4 × (5 + 3) = 4 × 8 =
32
not 4 × (5 + 3) = 20 + 3 =
23
(wrong)
Exponents (Powers, Roots) before Multiply, Divide, Add or Subtract
yes 5 × 22 = 5 × 4 =
20
not 5 × 22 = 102 =
100
(wrong)
Multiply or Divide before you Add or Subtract
yes 2 + 5 × 3 = 2 + 15 =
17
not 2 + 5 × 3 = 7 × 3 =
21
(wrong)
Otherwise just go left to right
yes 30 ÷ 5 × 3 = 6 × 3 =
18
not 30 ÷ 5 × 3 = 30 ÷ 15 =
2
(wrong)
How Do I Remember It All ... ? PEMDAS !
P
Parentheses first
E
Exponents (ie Powers and Square Roots, etc.)
MD
Multiplication and Division (left-to-right)
AS
Addition and Subtraction (left-to-right)
Makes me brain list