Iam having trouble with multiplying negative numbers and positive numbers

So, negatives are tricky. But here's a nice rule for it:

1). negative (-) times negative (-) is positive because like signs, when multiplied are always positive.

2). negative (-) times positive (+) is negative because, different signs, when multiplied, are always negative.

3). positive (+) times positive (+) is positive because, again, like signs, when multiplied, are always positive.

Let's do the first 2 together:

So -5 times 7. First, let's ignore the signs and do the numbers first. 5 * 7 = 35. Cool. Now lets do the signs. Since it's a negative times a positive, it'll be negative. So your answer is -35.

Now lets do -8 times -4. Ignore the signs. 8 * 4 = 32. Now the signs. It's negative times negative. So it'll be positive because like signs, when multiplied, will always be positive. So the answer to the second one is 32.

Hope this helps!!

out of these options:

ability to burn paper

pure sodium reacting violently with water

the boiling point of water

helium does not tend to react with anything

i would say this is a physical property:

helium does not tend to react with anything

why? :

i said helium does not tend to react with anything because well, it reacts to ! but ability to burn paper, pure sodium reacting violently with water, & the boiling point of water are chemical or

physical properties: the properties of a substance that can be observed without changing the chemical makeup of the substance

chemical properties: properties of a substance relating to the chemical nature and reactivity of the substance