8/21/2021

22: A Simple Addition

How do you calculate 2 + 3 x 7? Is the answer 35 or is the answer 23? To know the correct answer, one must know the correct order of operations with respect to addition, subtraction, multiplication, division, etc.

Rule 20:
Multiplication and division must be completed beforeaddition and subtraction.

2 + 3 x 7 = 2 + 21 = 23 is the correct answer to the above question.

How do you calculate (2 + 3) x (7 - 3)? Is the answer 32,20 or is the answer 14? To know the correct answer, one must know the correct order of operations with respect to addition, subtraction, multiplication, division, and with respect to parenthesis.

This basic online calculator is similar to a small handheld calculator and has the standard four functions for addition, subtraction, division and multiplication. Like most 4-function calculators it also includes keys for percent, square, square root and pi. This basic calculator has decimal precision up to 10 digits and offers these functions. Unit 2 the derivativeap calculus. About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features Press Copyright Contact us Creators.

Rule 21:
Expressions in parenthesis are treated as one numberand must be calculated first.

(2 + 3) x (7 - 3) = 5 x 4 = 20 is the correct answer to the aboveproblem

22: A Simple Addition Worksheets

How would you calculate [3 + 7 - (2 + 3 x 6) +2 x 5 -7 +1]?

Rule 22:
If parenthesis are enclosed in other parenthesis, work from the inside out.

In the expression, , the expression (2 + 3 x 6) is the inner most parenthesis and must be calculated first. 2 + 3 x 6 = 2 + 18 = 20.

The expression is now modified to . The next parenthesis to be calculated is 7 - 20 + 2 x 5 = 7 - 20 + 10 = - 13 + 10 = - 3.

The expression is now reduced to [3 + {-3} - 7 + 1] = 0 - 7 + 1 = - 6.

How would you calculate .

Rule 23:
The parenthesis instruct you to simplify theexpression within the parenthesis before you proceed. The divisionsymbol has the same role as the parenthesis. It instructs you totreat the quantity above the numerator as if it were enclosed in aparenthesis, and to treat the quantity below the numerator as if itwere enclosed in yet another parenthesis. When you complete thattask, you have what appears to be two fractions that you are adding.Not so! can bewritten andmultiplication must be completed before addition within eachparenthesis.

= Bothparenthesis have been simplified. Now perform the multiplication toyield . The last thing todo is the addition.

If you would like more examples and problems to work click on the appropriate word.

Copyright © 1999-2021 MathMedics, LLC. All rights reserved.
Contact us
Math Medics, LLC. - P.O. Box 12395 - El Paso TX 79913 - USA
users online during the last hour

Calculator Operations

This basic online calculator is similar to a small handheld calculator and has the standard four functions for addition, subtraction, division and multiplication. Like most 4-function calculators it also includes keys for percent, square, square root and pi. This basic calculator has decimal precision up to 10 digits and offers these functions:

  • mc = Memory Clear: clear calculator memory
  • m+ = Memory Plus: add displayed value to memory
  • m- = Memory Minus: subtract displayed value from memory
  • mr = Memory Recall: display the memory value
  • CE = Clear Entry: clear current display value, changes to AC
  • AC = All Clear: clear all and start a new operation
  • √x = Square Root: take the square root of the displayed value and display it
  • +/- = Plus/Minus: change the sign of the displayed value from positive to negative or vice versa
  • π = pi: display the value of π as 3.141592654 to use in a calculation
  • x² = Square: square the displayed value and display it
  • R2 = Round to 2 decimals: round the current display value to 2 decimal places such as in money or currency format
  • R0 = Round to 0 decimals: round off the current display value to 0 decimal places
  • % = Percent: use displayed value to calculate a percentage

22: A Simple Addition Subtraction

Accessible Calculator Features

Zoom: Increase the size of the calculator in your browser using your browser's zoom feature. The size of the calculator, text and buttons changes proportionately.

Touch Screen Zoom: Increase the size of the calculator on your touch screen by zooming with your fingers. The size of the calculator, text and buttons changes proportionately.

22: A Simple Addition Anchor Chart

22:

Text Size: In some browsers, such as Chrome desktop, you can change the text size in your browser settings and the size of the calculator, text and buttons will get larger or smaller proportionately.

Keyboard Control: You can use the calculator without a mouse by tabbing among the calculator keys. Press 'Enter' when a key is focused. This method can be arduous however, since you must tab through all keys in sequence.

Number Keypad Control: You can use the calculator with with most Number Pads and Keyboards in the most popular browsers for numbers, clear, and the basic functions of addition, subtraction, multiplication, and division and delete/backspace.

22: A Simple Addition Worksheet

Please Contact Me if you have any suggestions.

Calculating Percentages

  • Multiplication and Division will convert the displayed value to a percent in decimal form and complete the operation when you press [=]
    • Example: find 20% of 25
    • Enter 25 x 20 % and the display changes 20% to 0.2
    • Enter = to complete the calculation 25 x 0.2 = 5. The answer 5 shows in the display.
  • Addition and Subtraction will add or subtract the percentage of a value
    • Example: add 20% to 25
    • Enter 25 + 20 % and the display changes to 5. (5 is 20% of 25)
    • Enter = to complete the calculation 25 + 5 = 30. The answer 30 shows in the display.
  • Tax Calculation
    • Example: add 6% tax to a purchase of $851
    • Enter 851 + 6 % and the display changes to 51.06. (51.06 is 6% of 851)
    • Enter = to complete the calculation 851 + 51.06 = 902.06. The answer 902.06 shows in the display.
    • Note: for other problems you might get an answer with more than 2 decimal places. Use the R2 key to round off to dollars and cents. Use R0 to round off to only dollars.