Post 2 Multiplying and Dividing Numbers and special note on ZERO.
- 4 times 5 = -20 50 divided by -10 = - 5 (- 8) 9 =-72 If multiplying or dividing by one positive number and one negative then the answer is negative. |
- 4(- 8) = +32 or 32 (-7)(- 6) = +42 or 42 -18 divided by - 3 = 6 If multiplying or dividing by a negative number and another negative then the answer is positive. |
+4(+ 8) =+32 You know a positive number multiplied or divided by another positive number yields a positive answer. |
HOW to write a Multiply in Algebra!In algebra we do NOT use the x or the dot for multiply.We write the numbers next to each other; some times we use parentheses. 3(6) or (3)(6) means multiply 3 and 6. |
You must use only two of the numbers at a time to determine their sign.Try these examples:A. -6(-7)(-4) = +42(-4) = - 168. The -6 times the -7 gives + 42. Then multiply by the -4. B. (-4)6(-2) = -24(-2) = +48 or 48. The -4 times the 6 gives -24. Then multiply by the -2. The rules for deciding the sign of the answer for multiplying and dividing are the same. The / symbol means divide by or is the fraction bar. It is also the divide key on the calculator. |
FRACTIONS:which ones are less than 1 whole? 5/8 or 8/5. And 9/11 or 11/9?And 14/7 or 7/14?DO YOU KNOW?5/8 means 5 divided by 8.This should give you a decimal number that is less than 1 whole if you complete the division.Do NOT confuse it with 8 divided by 5 or also called 8-fifths.This is more than 1 whole. It is 1 and 3/5.Be sure you know which "way" to divide.Do the division for the 5/8 and send me your answer in an email Click: Susan O. Johnsey . |
WHAT ABOUT ZERO in division? Zero is well understood with adding, subtracting and multiplying. But it is a bit peculiar, some would say, when it comes to division.Look carefully:0/4 = 0 4/4= 1 4/(-4)= -1 0/-4 = 0 -4 / 4 = -1 -4/(-4) = 1 4/0 is undefined. Division by zero and Division into zero are quite different. |
A common fraction that most students know is 4/5, that is, 4-fifths. 4/5 means 4 divided by 5 . Will the division give you a number larger than 1 or smaller than 1?? Can you read these fractions? Watch out!! 6/5 is read "6-fifths" 5/5 is read "5-fifths" and equals 1 whole 5/4 is read "5-fourths". OK? Keep going please: 5/3 is read_______ 5/2 is read_________ 5/1 is read__________ 5/3 is read 5-thirds 5/2 is read 5-halves 5/1 is read 5 wholes 5/0 is read_______ oops what did you say here? 5- zeroths!!! what is that? there is no such fraction! And what about the 5/0? 5/0 is undefined (have you ever heard of 5-zeroths? I hope not! ) 5/0 means 5 divided by 0. There is not a simple number answer that can be given. This is studied in Calculus so I will tell you for now to just know division BY zero is undefined. Do not confuse it with division into zero. 0/4 = 0 |
All division BY zero is undefined:6 /0 or 6 divided by 0, and even, 0/0 are undefined.0 divided by 3 (zero-thirds) is 0, but 3 divided by 0 (that is 3-zeroths) is undefined. |
