1 1. One day, tens of thousands of diamonds were stolen from a jewelry store in a city. After reporting the case, after three months of investigation, it was found that the perpetrator was definitely one of A, B, C and D. After trial, the confessions of these four people were as follows:

I was in another city the day the diamond was stolen, so I'm not a criminal.

Ding is a criminal.

C: B is a thief. I saw him selling diamonds on the black market three days ago.

D: B bears a grudge against me and deliberately sets me up.

Because the confession is inconsistent, it is impossible to determine who is the criminal.

After the polygraph test, I learned that only one of these four people was telling the truth, so who was the criminal?

12. There are 253 students in the fifth grade of Qingfeng Primary School. The school organized a math group, a recitation group and a dance group. It is stipulated that everyone should participate in at least one group and at most two groups. How many people should participate in the same group? 1, if 0.0000000 12 is simply written as 0.00...(8 zeros), there are three decimal places below.

A = A = a=0.00....(99 zeros) 12, b=0.0000 ... (one hundred zeros) 025, C = 0.00...( 10 1 zero) 08.

Find a÷b(b×c)-(a+b)=?

2.4.03+4.06+4.09+4. 12+...+5.95=?

3.(3.6×0.75× 1.2)÷( 1.5×24×0. 18)=?

4. The sum of two numbers is 15.95. If the decimal point of a smaller number moves one place to the right, it is equal to a larger number. What is the decimal point?

5. After moving the decimal point of a number to the left by two places, the number obtained is less than the original number 15.84. What is the original number?

6.a=0.00。 (100 zeros) 04, B = 0.00...( 10 1 zero) 05

a+b=( ) a-b=()

a×b=( ) a÷b=()