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.

Problem

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.

Solution

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!