1) -15
2) 5
3) -13
4) -4
5) 5
6) 14
7) 0
8) -8
9) -8
10) 7
These are very easy, when subtracting a negative from a positive think of it as just plain subtraction. When adding a negative to a positive, again, think of it as subtraction. When subtracting two negatives it's basically addition but you final answer should have a negative sign.
Hope I could help! :)
You just use what you already know. You know that 1 week is equal to 7 days so you just do 1 * 7 = 7 or 1 week. Then 54 * 7 = 378
