Explain how you can tell without calculating whether the sum of a positive number and a negative number will be positive, negati
2 answers:
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<h3>Answer: 4368 square feet</h3>
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Explanation:
Check out the diagram below
I drew a rectangle with dimensions 56 ft by 78 ft.
Then I broke up the 56 into 50+6, and I broke up the 78 into 70+8
The reason for this is because it's fairly easy to multiply the areas of each smaller rectangle at this point
- In the upper left corner, we have an area of 50*70 = 3500. Note how this is basically 5*7 = 35, but we tack on the two zeros (from 50 and 70 combined)
- In the upper right corner, we have an area of 70*6 = 420
- In the lower left corner, we have an area of 50*8 = 400
- In the lower right corner, we have an area of 6*8 = 48
Add up all the areas found: 3500+420+400+48 = 4368
As a way to check, using your calculator shows that 56*78 = 4368