Interesting problem in primary school mathematics: chalk has 8 1 box, of which 80 boxes have the same quality, and one box is lighter than others. How many times do you have to weigh it to find it?

Interesting problem in primary school mathematics: chalk has 8 1 box, of which 80 boxes have the same quality, and one box is lighter than others. How many times do I have to weigh this box of chalk?

The 8 1 box is divided into three parts, and each part has 27 boxes. It is easy to understand that 1 time can confirm that these 27 boxes are inside.

Twenty-seven boxes were divided into three parts, 9 boxes in each part, and weighed 1 time to determine which 9 boxes were the same.

Divide 9 boxes into 3 parts and weigh 1 time to determine which 3 boxes are the same.

Divide three boxes into three parts, each part is 1 box, and then call it 1 time. Determine which one is 1 box in the same way.

It takes four times to find this box of chalk.

Mathematical manuscript

What is the main content of the ACT exam?

65438+1celebrities who died on October 5th.

How should first-grade children practice oral arithmetic? What problems should we pay attention to?

He's a sports student in Henan, with a culture course of about 470. He is good at sports and wants to enter a comprehensive university in Beijing. What's the point?

How to learn math and physics well in senior high school?

Mathematical problems in preschool classes

How active is 1 100 million?

Problems of Ancient Mathematics in China

The topic of interest rate and income in monetary banking