Compare temperatures involving negative numbers
What temperature is 8 degrees more than minus 5 degrees Well, we have our number line thermometer here, so if we start at minus 5 and count on 8, we get to 3 degrees, so if its minus 5 degrees and the temperature goes up by 8 degrees, we get 3 degrees. But rather than using a number line to count through zero, lets try a quicker method: if we start on minus 5 degrees, we know that adding 5 degrees will take us to 0 degrees. Then, from 0 degrees, we can add 3 degrees to get 3 degrees. So, because we added 5 and then added 3, we added 8 altogether: so, if you need to add something to a negative number, you can add as much as you need to make 0, then add the Now, what temperature is 7 degrees less than 3 degrees Well, we have our number line, and when we count back, we get minus 4, so if the temperature starts at 3 degrees and then gets 7 degrees colder, the new temperature is minus 4 degrees. But again, lets use a quicker method, rather than relying on our number line: if we sta
|