document.write( "Question 69927: I need to know the rules for signed number arithmetic ie: when adding like signs..., unlike..., subtraction, multiplication, division... Thank you! \n" ); document.write( "
Algebra.Com's Answer #49832 by bucky(2189)\"\" \"About 
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Addition
\n" ); document.write( "(1) When adding two numbers having the same signs, add the numbers and prefix the answer
\n" ); document.write( "with the common sign.
\n" ); document.write( "Examples:
\n" ); document.write( "(+3) + (+6) = +9 and
\n" ); document.write( "(-4) + (-2) = -6
\n" ); document.write( "(2) When adding two numbers of unlike signs, subtract the smaller number from the larger number,
\n" ); document.write( "and give the answer the sign of the larger number. Examples: (+9) + (-6) = +3 and
\n" ); document.write( "(-9) + (+6) = -3
\n" ); document.write( "Next:
\n" ); document.write( "Subtraction: Change the sign of the quantity being subtracted. Then follow the rule for addition.
\n" ); document.write( "Examples:
\n" ); document.write( "(+5) - (+3) =?? Keep the +5 but change the +3 to -3. Then follow addition rule (2) signs by
\n" ); document.write( "subtracting 3 from 5
\n" ); document.write( "and prefixing the answer 2 with the same sign as the bigger number, that is the sign of
\n" ); document.write( "the 5 which is +. Therefore, the answer is + 2
\n" ); document.write( "Another example. (+5) - (-9) =? Change the sign of the number being subtracted and
\n" ); document.write( "follow the rules of addition. When you change the sign the -9 becomes + 9 which has the
\n" ); document.write( "same sign as the +5. Therefore, follow addition rule (1). Add the two numbers to get 14
\n" ); document.write( "and add the common sign which is +. The answer is +14.
\n" ); document.write( "Another example. (-9) - (-5). Change the sign of the -5 so it becomes +5 and add it to
\n" ); document.write( "-9. Use addition rule 2 because the two numbers (+5 and -9) have different signs.
\n" ); document.write( "Subtract the two numbers (9-5) and prefix the sign of the larger number (9 which has a
\n" ); document.write( "minus sign). The answer is -4.
\n" ); document.write( "Another example: (-8) - (+6) = ? Change the sign of the +6 so that it becomes -6. Then
\n" ); document.write( "add the -8 to the -6 by following addition rule 1. Since the numbers have the same sign, add
\n" ); document.write( "the numbers (8+6) to get 14 and prefix the common sign of the two which is the negative sign. The answer is -14.\r
\n" ); document.write( "\n" ); document.write( "Multiplication.
\n" ); document.write( "(1) Multiply the two numbers. If they both have the same sign, the answer will be positive.
\n" ); document.write( "Examples: (+4) * (+5) = +20 and (-4)* (5) = +20. [That's correct, both answers are + 20
\n" ); document.write( "because in both examples the signs of the numbers being multiplied are the same ... in
\n" ); document.write( "the first example they are both + and in the second case they are both -.]
\n" ); document.write( "(2) Multiply the two numbers. If they have different signs, the answer will be minus.
\n" ); document.write( "Examples: (+4) * (-5) = -20 and (-4) * (+5) = -20\r
\n" ); document.write( "\n" ); document.write( "Division.
\n" ); document.write( "The same general idea as multiplication, except this time you divide the two numbers and
\n" ); document.write( "use the rule that if both the numbers have the same sign the answer is +, but if the two
\n" ); document.write( "numbers have opposite signs the answer will be -.\r
\n" ); document.write( "\n" ); document.write( "Example: \"%28%2B8%29%2F%28%2B2%29+=+%2B4\" but \"%28%2B8%29%2F%28-2%29+=+-4\" and \"%28-8%29%2F%28%2B2%29+=+-4\" but
\n" ); document.write( "\"%28-8%29%2F%28-2%29+=+%2B4\"\r
\n" ); document.write( "\n" ); document.write( "Hope this helps you to get a grasp of the basic rules. The rest involves lots of practice
\n" ); document.write( "until they become automatic to you.\r
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