You can get the tens digit of any number <em>n</em> by computing the quotient
(<em>n</em> (mod 100)) / 10
and ignoring the remainder.
Taking the given sum (mod 100) gives
7! + 8! + … + 2006! ≡ 7! + 8! + 9! (mod 100)
since the last 1997 terms (i.e. 10! up to 2006!) in the sum are multiples of 100. That is,
• every term beyond 100! is obviously a multiple of 100
• every term beyond 25! contains a factor of both 4 and 25
• every term beyond 10! contains two factors each of both 2 and 5 (i.e. every factorial term contains 4, 5, and 10)
The remaining sum is easy to compute by hand:
7! + 8! + 9! = 7! (1 + 8 + 8 × 9) = 5040 × 81 = 408,240
so the tens digit is 4.
Answer:
0.81418097052
Step-by-step explanation:
just put it in a calculator?
Answer:
You cannot list every single multiple of 15, but some of them are 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 165, 180, and 195.
Step-by-step explanation:
Answer:
Possible answers
- A lot of dishes he has to do
- He selling it
- He has no shampoo or body wash so washes up with dish soap
- Pranking someone with it
I dont know <:)
Step-by-step explanation:
Answer:
6.67 hours
Step-by-step explanation: take 5585/837
