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# The calculator confusion

One person sent me this message:
What is the difference between normal calculator and mobile phone calculator? Have you ever checked?
Calculator of mobile phones v/s normal calculators give different results….
See the difference between a Mobile calculator and a Normal calculator….
Normal calculator
4+4÷4=2
Mobile calculator
4+4÷4=5
Once again....
Normal calculator: 4+4x4=32
mobile calculator: 4+4×4=20
He also gave this explanation: normal practice is to calculate  starting from left to right side ... mobile phone calculator does the opposite ----so don't use the mobile calculator!
Krishna: I have a scientific calculator and it gave me the same answers as the mobile calculator. There is no difference at all. I don't have an ordinary calculator. So I consulted some experts on the subject and they gave me this explanation ....
This is what happens if you don't enter the data properly ....
1. First of all, 2 is the wrong answer.
2. Teachers coaching students in the subject arithmetic  usually ask  Qs like these : What is half of 56 ? The student's reply these days usually will be : Which half ? Left side half or right side half ? Left side means the answer is 5 and if you want the right side half, it is 6 ! Thinking objectively, the students are  also technically as correct as the teachers because the question was asked in English and not in the language of mathematics which is, 56÷2=?
3. Mathematics is comparatively an absolute science because its conventions are clearly defined and it generally needs no judiciary to settle a dispute.
4. Now take the case of 4+4÷4. In English you ask, what is 4 plus 4 divided by 4 ? The answer could be 2 as well as 5 because (4+ 4)=8÷4 =2 and 4+(4÷4)=5. The convention used here in arithmetic is the BODMAS RULE. It just states that, in any arithmetical operation, the priority of operations are as follows :
5. Take the BRACKETS OFF FIRST.
6. THEN THE DIVISION.
7. THEN THE MULTIPLICATION
9. THEN THE SUBTRACTION.
10. Following this rule, in 4+4÷4, the division is operated first which gives, 4÷4=1. Then the addition gives, 4+1=5 which is the correct answer.
11. Your discrete calculator is programmed by a programmer who does not know the Bodmas Rule and the mobile calculator is programmed by a programmer who knows the BODMAS RULE. The calculator , is in itself a dumb entity unless it is powered by artificial intelligence (AI.)  Scientific calculators (and most mobile calculators) follow the BODMAS rule. They are programmed to do so.  If we want the same answer in a normal calculator,the data should be fed as 4+(4÷4).  So the answer of the mobile calculator is correct, and in the case of a normal calculator , one has to take the BODMAS rule into account and input the sum accordingly.
12. Some years back a report appeared in the media that NASA (NATIONAL AERONAUTICS AND SPACE ADMINISTRATION) had lost millions of dollars in a failed rocket launch because just ONE HYPHEN (-) was missed by the computer programmer.
13. FOR YOUR FUTURE : IF YOU WISH TO PROGRESS TO ADVANCED CALCULATIONS THAT INCLUDE POWERS OF NUMBERS, YOU MAY SWITCH TO THE MNEMONIC “BEDMAS” or “PEMDAS" . Bodmas, Bedmas and Pemdas all mean the same, but keeping in mind the simplicity in explanation needed for a beginner who has no need for powers of numbers, this is an oversimplification of Bodmas.
14. BoDMAS stands for:

Bo - Bracket of

D - Division

M - Multiplication

S - Subtraction

In 4 + 4 ÷ 4 we do division first and then we add according to BoDMAS rule.

4 + 4 ÷4 = 4 +1 = 5

15. PEMDAS —Parenthesis, Exponent, Multiplication, Division, Addition then Subtraction.

So almost all the people I spoke to said scientific calculators and mobile calculators calculate accurately.

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