Looking at number 4, you first have to look at the information that you have:
On tuesday he practiced for 1 5/6 hrs
Monday he practiced for 7/10 hrs
He is supposed to practice for 1 1/4 hr.
You could write questions like:
How much more did Marco practice on Tuesday than he is supposed to practice?
This works because it does indeed involve subtraction, you would be subtracting the amount that he should have practiced from the amount of time that he did practice.
If I didn't answer the question, please message me and I will clarify!
It is 17 if you do the math and do the multiples of 187 and 578
The expression has 3 terms
For this case we have the following number:
2.25 x 10-4
We observe that it is written in exponential notation.
The exponent is negative, therefore, we must move the point to the left.
We have then:
2.25 x 10-4 = 0.000225
Answer:
0.000225