Enter or edit numeric value with unit answers

Overview: Answering on a computer or mobile device

These instructions apply to entering answers in either the Value or Units answer boxes.

Toolbar for these questions on a computer:
Toolbar for these questions on a mobile device:

	Enter answers on a computer	Enter answers on mobile device* (tablet or smartphone)
Toolbar	Use the Templates menu for special formats like exponent and fraction. Use the Symbols menu for symbols like percent and degrees. To undo, redo, and reset the answer box to its original state: Use toolbar buttons. To view or print keyboard shortcuts or this Help topic: Click buttons on the right.	To begin, tap in an answer box for the toolbar to appear below. Choose buttons from the Letters, Numeric, Templates, and Symbols menus to compose your answer. To undo, redo, and reset the answer box to its original state: Use toolbar buttons on the right.
Keyboard for letters and numbers	Use your physical keyboard to enter letters, numbers, and other characters. See info below for characters you can or cannot use in your answers.	Choose either the Letters menu or the Numeric menu for alphanumeric characters and some math symbols. To switch between lowercase and uppercase keys: Choose the arrow button from the Letters menu.
Keyboard shortcuts for special formats(like subscript)	It can be faster to use keyboard shortcuts instead of the Templates menu to insert special formats.	For keyboard shortcuts that begin with \ (backslash), choose \ from the Letters menu.
Cursor control in your answer	Use your keyboard arrow keys (, , , ) to move the cursor in your answer or between Value and Units answer boxes. It can be easier to use arrow keys instead of a mouse or other input device to reposition your cursor.	Use your finger or other input device to position the cursor in an answer or in the other answer box. For finer cursor control on a phone: Enlarge your view of the answer box before moving the cursor. If cursor control on your phone is challenging: Consider using your computer or a tablet.

Characters you can or cannot use for value

You can enter any of the numeric characters and symbols shown in the table below.
Integers (such as 1024), decimal numbers (such as 1.024), and scientific notation (such as 5.2*104) are all acceptable. For scientific notation, you can either use your keyboard or choose this format from the Templates menu.

You cannot enter commas, algebraic expressions, or calculations. The built-in calculation feature is not available for Value answers.

Acceptable numeric characters and symbols	Notes	Available from this menu (on mobile devices)
0-9	You can enter these characters directly or into a special format, like a subscript.	Numeric
*	For multiplication	Numeric
.	For decimal point	Numeric
^	For exponent format	Numeric
()	When you enter the first part, it displays in red until you close the expression.	Numeric
/	For fraction format	Numeric

Insert exponent, subscript, fraction, dot, or scientific notation for value

To enter...	Choose this from the Templates menu:	Or, enter this keyboard shortcut:	Examples/Notes Instead of pressing or below, you can also reposition your cursor.
Exponent (Superscript)		^ (caret)	To enter , either: Enter 10, choose , and enter 3 Enter: 10^32
Subscript		_ (underbar)	To enter , either: Enter 5, choose , and enter 3 Enter: 5_3
Fraction	$fraction template format$	/	To enter , either: Choose $fraction template format$ , type 2 , press , and enter 3 Enter: 2/3 or /23 To move between the top and bottom parts of a fraction: Use the arrow keys from your computer keyboard or reposition your cursor using an input device.
Dot (for multiplication)		* (asterisk)	To enter 79 either: Enter 7, choose , and enter 9 Enter: *79**
Scientific notation		* (asterisk for multiplication dot) ^ (caret for exponent)	To enter 5.2103, either: Choose , type 5.2, and enter 3 in the exponent format. Enter: 5.210^3** To edit the provided "10": Press the right arrow key to position your cursor, and then delete or add digits using your keyboard. You can also delete by choosing Delete from the provided toolbar.

Important: Rules for entering units

Use only unit abbreviations. Do NOT add a period after any unit.
Units are case-sensitive.
Mastering can accept as correct a unit answer that is equivalent to the correct answer. For example, if the correct answer is 2 V and you enter 2000 mV, you will receive full credit. See next point for an exception to this rule.
Both SI (International System of Units) and U.S. Customary units are represented on the list of units that Mastering recognizes, so you can gain credit by answering correctly using either an SI unit or a US Customary unit.
Exception: When a question asks you to answer using a specific unit system, you must answer in that unit system. If you answer using the incorrect unit system, you will lose an answer attempt and any associated credit, even if your answer would otherwise be considered equivalent.
For multiplication in compound units, you can enter either * (centered dot) or - (dash). For example, and ft-lb are accepted as equivalent correct units.

Unit forms you can enter

Single unit, such as N, J, , , and C
Single unit with prefix, such as MeV or F
Compound unit, such as Nm, ft-lb, kg-m/s, m/s
To indicate multiplication in compound units: Use either * (displays as the centered dot) or -.
Compound unit with prefix, such as kNm

Acceptable characters and symbols for units

In addition to the symbols in this table, you can enter the symbols for angstrom, degrees, mu, ohms, and percent. See section below for instructions.

Acceptable characters and symbols	Notes	Available from this menu (on mobile devices)
a-z, A-Z	You can enter these characters directly or into a special format, like a fraction.	Letters
()	When you enter the first part, it displays in red until you close the expression.	Numeric
*	For multiplication of units	Numeric
-		Numeric
/	For fraction format	Numeric
^	For exponent format	Numeric
_	For subscript format	Numeric
\	To begin a keyboard shortcut, such as \deg (for degrees)	Letters

Insert exponent, subscript, fraction, or dot for units

To enter...	Choose this from the Templates menu:	Or, enter this keyboard shortcut:	Examples/Notes Instead of pressing or below, you can also reposition your cursor.
Exponent (Superscript)		^ (caret)	To enter m4, either: Enter m, choose , press , and enter 4. Enter: m^4
Subscript		_ (underbar)	To enter , either: Enter O, choose , and enter 2 Enter: O_2
Fraction	$fraction template format$	/ To enter a unit with multiplication in the numerator, such as : Choose $fraction template format$ from the Templates menu for the right format. (You cannot use /.)	To enter , either: Choose $fraction template format$ , enter mol , press , and enter h Enter: mol/h or /molh To move between the top and bottom parts of a fraction: Use the arrow keys from your computer keyboard or reposition your cursor using an input device.
Dot (for multiplication)		* (asterisk)	To enter ftlb, either: Enter ft, choose , and enter lb Enter: *ftlb**

Insert symbols angstrom, degrees, mu, ohms, or percent for units

To enter this symbol...	Choose this format from the Symbols menu	Or, enter this keyboard shortcut
(Angstrom)		\AA
(degrees)		\deg
(mu)		\mu
(Ohm(s))		\Omega
% (percent)		\percent

Navigate within your answer

The way to move the cursor in an answer depends on whether you are working with a physical keyboard.

Computer users: Use your keyboard arrow keys (, , , ) to move the cursor in your answer. Note that the left and right arrow keys can move the cursor vertically within an expression. You can also use a mouse or other input device to reposition your cursor in an answer, but using the arrow keys may be easier.
Smartphone and tablet users without a physical keyboard: Use your finger or other input device to position the cursor in your answer. For finer cursor control on a phone, enlarge your view of the answer box before moving the cursor. If moving the cursor on your phone is a challenge: Consider completing the question on your computer or tablet.

Discontinue entering special format values (like exponent) in your answer

When you finish entering a value in a special format (for example, the numerator of a fraction), you need to move the cursor outside of the format area. The way you do this depends on whether you are working with a physical keyboard.

Computer users: Use your keyboard arrow keys (, , , ) to move outside of a special format area in your answer. You can also use a mouse or other input device to reposition your cursor within or outside of a special format, but using the arrow keys may be easier.
Smartphone and tablet users without a physical keyboard: Use your finger or other input device to position your cursor outside of any special format area. For finer cursor control on a phone, enlarge your view of the answer box before moving the cursor. If moving the cursor on your phone is a challenge: Consider completing the question on a computer or tablet.

Edit a value or unit answer (undo, redo, reset, delete, or copy and paste)

Click in or choose the Value or Units answer box you want to edit. After you click in or make edits in one box, you can move to the other answer box using the right arrow key right arrow or left arrow key from your keyboard.

Edit	Instructions
Undo	Choose undo to undo your previous actions in reverse order—one action per click (or tap/touch, on a mobile device). Alternatively, press Ctrl+Z (Windows) or Command-Z (Mac OS) from your computer keyboard.
Redo	Choose redo to redo the previous action. Alternatively, press Ctrl+Y (Windows) or Command-Y (Mac OS) from your computer keyboard.
Reset	Choose reset to clear your workspace. If you want to start over: This is the easiest way!
Delete	Delete button: Deletes individual characters from left to right. You can also use the Delete key on your computer keyboard. For a specially formatted expression (such as a fraction): Press Delete once to select the item, and then press Delete again to delete it. Backspace key (on a keyboard): Deletes individual characters from right to left. For a specially formatted expression (such as a fraction): Press Backspace once to select the item, and then press Backspace again to delete it. Keyboard shortcut to cut: You can use standard keyboard shortcuts (Ctrl-X for Windows, Command-X for Mac OS) to cut an answer or parts of an answer. See Step 1 below for details about selecting characters.
Copy and paste	These instructions apply when using a computer. Select the part of the expression you want to copy. To select individual characters or specially formatted expressions (such as a fraction): Click and drag your input device or hold down the Shift key and press either the left or right arrow key. Continue to press the arrow key for each additional character or format. Copy using a standard keyboard shortcut: Ctrl+C (Windows) or Command-C (Mac OS). Paste using a standard keyboard shortcut: Ctrl+V (Windows) and Command-V (Mac OS).

Practice entering numeric answers with units

Open the Introduction to Mastering assignment and select the Introduction to Numeric Answers with Units item. This assignment provides practice items for different kinds of questions.

You can usually return to this assignment anytime during the course, even after its due date. If you completed this assignment, you can usually rework its items for practice.

Open these instructions as you answer questions

Select Help from the answer box toolbar then choose Enter numeric value with unit answers on the page that opens.

Select Keyboard shortcuts for how to use your keyboard to answer value and units questions. See also the acceptable units list.