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Day 4: Adding and Subtracting IntegersDescription: Adding and Subtracting Integers


Using formulae to add and subtract numbers that we are not familiar with.

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Adding and subtracting Integers part 1

Moscow is 7 degrees hotter than Leningrad.

If Leningrad is 4 degrees, what temperature is Moscow?

(#Leningrad) + (#hotter Moscow is)

(#Leningrad) + (#hotter Moscow is ) is our formula!

It means Add the two values we have together.


When adding a whole number to an integer think of the integer as the total number of people who have got on a bus (if the number is positive) or the total number of people that have got off the bus (if the number is negative).  Now add a whole number of people to this value.

E.g.   +10  + 7  = +17

  -3 + 7  means that more people get on the bus (+7) than have got off the bus (3) so overall +4 people have got on the bus.

-10 + 7 means that more people had got off the bus (10) than got on the bus (+7) so overall 3 people have got off the bus, so the answer is -3