How can you decide if the difference of two numbers is positive, negative, or zero without calculating?

Question

How can you tell the SUM of two numbers is positive or negative?

How can you decide if the DIFFERENCE between two number is positive or negative?

Answer 1

SUM:
If the numbers are the same sign, the sum will be the same sign as the numbers.
If they are different signs, the sum will be the same sign as the number with the largest size.

DIFFERENCE:
If the numbers are of different signs, the difference will be the same sign as the first number.
If the numbers are of the same sign, the difference will be the same sign as the numbers if the first number has the larger size, and the opposite sign to the numbers if the second number has the larger size.

Answer 2

If both are positive, their sum must be positive.
if both are negative, their sum is negative. Otherwise, if the positive number looks bigger than the negative, the sum is positive. If the negative number is larger than the positive number, the sum is negative.
Apply similar rules for differences. Sometimes, it is difficult to guess.
difference: -5, -8 positive
difference: -8, -5 negative
and so on.

Answer 3

If the number being subracted is bigger than the original number, the result would be negative
If you add a negative number to a positive number and the negative number is a bigger digit, it will come to a negative result also

Answer 4

negative 5+ poistive 3

5 is bigger than 3 so it is still a negative because any number smaller than 5 will be negative. Unless the 3 was negative in which case 2 negatives added together will always be negative.

Answer 5

Mathematics is all about canculating(bear in ur mind). But, there's way for u to tell the sign of a number for a question. In the SUM of 2 nu:
a) if the 1st number is a +ve n the 2nd nu is +ve,then d answer is +ve;
b) if the 1st nu is +ve n the 2nd nu is -ve but the 1st nu is greater than 2nd nu [it is a little bit trickier at ds point] then d anwswer is +ve,
c) if the 1st nu is +ve n the 2nd nu is -ve but the 2nd nu is greater than 1st nu [e.g 5+ (-8) in d sense d 8>5] then d anwswer is -ve,
d)if d 1st and 2nd nu are -ve, then d answer should be -ve also
In d case of d DIFFERENCE btwn 2 nu:
a) if the 1st nu and 2nd nu are +ve where 1st nu is greater dn 2nd nu, then d answer is +ve
b) if the 1st nu and 2nd nu are +ve where 2nd nu is greater than 1st nu, then d answer is -ve
c)if d 1st nu is +ve and 2nd nu is -ve, the answer will always be +ve
d)if d 1st nu is -ve and 2nd nu is +ve, the answer will always be -ve
e)if d 1st nu is -ve and 2nd nu is -ve, the answer will be +ve if 2nd >1st [e.g (-5)-(-11)=6 where 11>5], while the answer can be -ve if 1st>2nd [e.g (-11)-(-5)=-6 where 11>5]
This rule is easy to apply for summation or substraction of simple numbers. However, the easiest way to know the sign is by using calculator (only if u type the quest and answer correctly). Happy calculating.

Answer 6

the sum will take the sign of the biggest (absolute fee)of the two numbers. If the two are advantageous the effect is advantageous. If the two are unfavourable the sum is unfavourable. The sum would be 0 provided that one huge style is unfavourable and one advantageous with the numbers equivalent to one yet another.

Answer 7

when you subtract two numbers with the same sign, just subtract and keep your sign , when your subtracting with two different signs such as -4- 3 you bring down the problem EXCEPT for your first number .. so your problem should say -4+-3 so it should be -7