Answer: 1

2. A tailor has a piece of woolen cloth, which is16m long. She cuts 2 meters from it every day and asks how many days later, she cuts the last piece of woolen cloth.

Answer: (8- 1)=7 (days)

3.a b c + c d c = a b c d

How much is abcd?

Answer: a= 1 c=9 d=8 b=0.

109+989= 1098

4. Ali said that under certain conditions, 4- 1 = 5, and said that Xiaoying can prove the correctness of this method by graphic means. After Ali produced the evidence, she had nothing to say. How did Ali prove the test? Guess.

Answer: A table with four corners has five corners after cutting off one corner with a knife.

5. The price of each bottle of soda is 1.00 CNY, and every two empty bottles can be directly exchanged for 1 bottle of soda. If you buy soda with 20.00 CNY, how many bottles can you drink?

Answer: 1. Buy 20 bottles, drink 20 bottles, and empty 10 bottles (20).

2.20 Empty bottles are 10 bottles, drinking 10 bottles and empty 10 bottles (10).

3. 10 5 bottles for empty bottles, 5 bottles for drinking, 5 bottles for empty bottles (5)

4.5 Empty bottles for 2 bottles, drink 2 bottles and empty 3 bottles (2)

5.3 Empty bottles are 1 bottle, drink 1 bottle and empty 2 bottles (1).

6.2 Empty bottles are 1 bottle, 1 bottle, and empty bottles are 1 bottle (1).

7. Borrow 1 empty bottle, * * 2 empty bottle, exchange 1 bottle for drinking, and exchange the empty bottle for someone else (1).

Total: 20+10+5+2+1+1= 40 bottles.

6. 1-70 1=2 spelled with matchsticks. Move a matchstick to make the equation hold.

Answer: 1+ 1 = 2 ... just put the minus sign on the 7 vertically.