Answer:
5040
Explanation:
Brianna has 7 choices for the first spot in her line up. Once she places that first block, she'll have 6 blocks left. So for spot two in the line up, there are 6 choices. And after she places that block, there will five blocks left to choose from for the next spot. Then four choices, then three, then two, then only one block left for the last spot in the line up.
Mathematically, we multiply together the number of choices for each spot in the line up.
7•6•5•4•3•2•1
This is 7! (the exclamation mark is an actual math symbol) read: "seven factorial"
7!
= 7•6•5•4•3•2•1
= 5040
Most scientific calculators and graphing calculators have a factorial (!) button.