If I have a positive and a negative number and I have to add them, as I do? Here’s one way to solve this problem: a useful refresher which was also asked in the tests.
Integers can be positive (the natural numbers) or negative. E.g. -9 -8 -7 -6 -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5 +6 +7 +8 +9
How to do if a problem is asking me to add them or subtract them from each other? We read, for example, a place math question.
Antonio Jade and participating in a quiz contest. For each correct answer, you assign two points and for every wrong answer you take away a point. The outcome of the race is this: Antonio gave 11 right and wrong answers 9, Jade gave 6 right and 14 wrong answers. What are the final scores of the two boys?
a) +13; +2.
b) +13; -2.
c) +2; +8.
d) +2; -8.
We must calculate the points that Anthony and Jade have gained, taking into account that for each correct answer, you assign two points and for every wrong answer you take away a point. Antonio gave 11 correct answers, then 11 x 2 = 22; but it has the wrong 9, and 22 must be removed 9, 22-9 = 13. So Antonio +13 points.
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We calculate those Jade. She gave six correct answers, then 6 x 2 = 12; but 14 did wrong, then 12-14 = -2.
So the right answer is +13; -2.
Of course, because the number to subtract 12 it is greater than 12, and then you get a negative result. Imagine having the coins: ye have 4 but you want to buy something that costs 6 coins. The shopkeeper all dates and 4, and then let a 2 coins debt. The shopkeeper will mark next to your name: -2!
To orient yourself in the calculation keep a line in mind with all the numbers: count what you have at the start and remove / add the number you need to calculate, moving on the line!
This way you have well impressed how to get the right result!