# Math Help - What are the Integer rules????? HELP???

1. ## What are the Integer rules????? HELP???

How can you remember integer rules, such as
a negative x a negative = positive
Plus:
what ARE the rules? I don't know!!!! How do you calculate a negative x a positive? WHAT ARE THE RULES??? I FAIL AT MATH!!!!!!

2. Originally Posted by ifailatmath
How can you remember integer rules, such as
a negative x a negative = positive
Plus:
what ARE the rules? I don't know!!!! How do you calculate a negative x a positive? WHAT ARE THE RULES??? I FAIL AT MATH!!!!!!
Let a and b be positive integers:

$a \times b = ab$

$(-a) \times b = (-1) \times a \times b = -ab$

$(-a) \times (-b) = (-1) \times a \times (-1) \times b = (-1)(-1)ab = ab$

$a \times (-b) = a \times (-1) \times b = -ab$

The integers are also closed under addition. Adding an integer to another always gives an integer. Ratios of integers are known as rational numbers. If a divides b, then the ratio a/b is an integer. If a doesn't divide b, then the ratio a/b is a rational number.

3. This was very helpful. Thanks!

4. ## hope this helps

when adding when the signd are the same -3 + -5 =-8 keep the same for the answer. if the signs are different, one pos one neg, then treat them both as pos for the moment. sub the smaller from the bigger, then give this answer to the larger 4 + -7 = -3. subtacting, subtracting can be converted to addition,because subtracting is the same as adding the opposite. once you have converted the sub to the add prob. use the rule for adding intgers. for example 2-5 can also be written as 2- +5. subtracting is the same as adding the opposite, so2- =5 can be written as
2+ -5 because the prob has been rewritten you can use the adding rules.
therefor, 2+ -5 =-3 or 7-3 = 7- +3 =7+ -3 = 4 another tip or short cut would be to make (-_) into possitive numbers when they are side by side
make them possitive If you are multipling if the signs are the same the
answer is poss. if the signs are different the signs are neg. If you are multipling more than two . the odd number of signs will be neg. and if theres an even number of neg signs the asnwer will be poss.
hope this helps