The 7+7 ÷7+7×7-7 is a type of quite tricky and confusing mathematical expression because by using different computing devices, you get two different answers.
I think this is another good time to exercise my brain and your brain too, and have fun solving this problem during free time.
There are many different answers given by different individuals like 0 and 8, but I want to focus on 50 and 56 because these are the most common answers that the calculators will give you.
The Google and other scientific calculators will give you the answer of 50, but the Windows calculator and other basic calculators will give you 56.
So what is really the right answer, 50 or 56?
First, there are two things that we need to consider: the Order of Operation and the Immediate Execution.
The simple Order of Operations in Mathematical expression states that you must perform first the expressions inside the parentheses and brackets then the exponents and radicals, followed by multiplication and division, then addition and subtraction.
The most popular mnemonics for this is PEMDAS which stands for Parentheses, Exponents, Multiplication, Division, Addition, Subtraction. (The Internet can give more answers if you want to explore further and learn about Order of Operations. Don’t be shy to google it.)
By using this Order of Operation to the above mentioned expression, you will get the answer of 50. Look at this solution:
- 7+7 ÷7+7×7-7=? perform the multiplication and division
- 7+1+49-7=? perform the addition
- 57-7=50 perform the subtraction
Now, when you use Immediate Execution, solving the expression from left to right without taking the Order of Operations into consideration, you will get the answer of 56. This is also known as Chain Calculation.
As I have mentioned, basic calculators often use this. Look at this solution:
- 7+7 ÷7+7×7-7=? solve it from left to right add 7 to 7
- 14÷7+7×7-7=? then divide 14 by 7
- 2+7×7-7=? then add 7 to 2
- 9 x7-7=? then multiply 9 by 7
- 63-7=56 subtract 7 from 63
The Application of the Expression
In hypothetical applications, both 50 and 56 may be the correct answer depending on the situation where the expression was taken.
If your answer is 56, this is the hypothetical situation and question:
You have 7 hens and your grandparents gave you 7 more hens. Because you are kind, you equally distributed all those hens to 7 persons including yourself (probably family circle). After that, your godfather gave you 7 hens as gift on your birthday. Later on, each of your hen laid 7 eggs but 7 of those eggs were cracked. How many good eggs were left?
If your answer is 50, this is the hypothetical situation and question:
You have 7 oranges and your colleague has also 7 oranges but he distributed them equally to each of his 7 friends, including you. Then your boss gave you 7 baskets with 7 oranges each. When you checked them, there were 7 rotten oranges and you threw them. How many of your oranges were left?
Now, if we are going to compare these two hypothetical situation, the second one is more realistic, but I am not saying that the first one is wrong.
So if you are going to ask me what is my final answer?
For now, I choose 50.
If you are a businessman, I know that your answer is 50 and 56. Why pick one if you can have both?
What do you think about my point? Feel free to comment.