Keywords: Math Contest, I am in Grade Two of Primary School.

This article is applicable to: the second grade of primary school.

Composition source:

This composition (600 words) is about the second grade of primary school (600 words). The topic is: My Math Competition (My math diary). Everyone is welcome to contribute.

My math contest.

After lunch, my mother called my sister and me together and said, "You have learned a lot about decimals. Let's have a math contest. " My sister and I nodded yes, and we were in high spirits. I thought to myself: the decimal knowledge I learned can be used!

The first question is this: Miss Li will buy some stationery from 80 yuan as prizes for the grade sports meeting. He first spent 45.6 yuan to buy eight photo albums, and prepared to use the remaining money to buy several ballpoint pens, each 2.5 yuan. How many ballpoint pens can Miss Li buy?

My sister and I quickly grabbed a pen and paper, used our brains quickly and calculated.

I think so: Miss Li spent 45.6 yuan on shopping in 80 yuan, and then used the rest to buy other things. It should be calculated as follows: 80-45.6=34.4 (yuan) 34.4/2.50= 13.76 (branch) is approximately equal to 13 (branch).

My sister thinks this way: 80 yuan first spent 45.6 yuan to buy eight photo albums, and is going to use the remaining money to buy some ballpoint pens. It should be calculated as follows: (80-45.6)/2.50= 13.76 (branch) is about 13 (branch).

Mother looked at our calculation results and smiled knowingly.

Let's answer the decimal oral calculation first:

1.7*0.4=?

"equal to 0.68." I blurted it out.

"Li Sen added a little," mom said.

7.77*0.2=?

My sister and I scratched our heads and calculated quickly.

"It should be 1.554." I figured it out again.

"Li Sen added another point," mom said.

Seeing that my sister was depressed, my mother encouraged her to continue to refuel.

Finally, there is a question of judgment. The question is this:

Integer multiplication and division algorithm is not suitable for decimal multiplication and division algorithm.

Right or wrong?

My sister said first, "Yes."

"Li Shu added a little," mom said.

As a result, Li Sen beat her sister 2-/kloc-0-. I jumped for joy.

Mother concluded: "winning or losing is not important, the key is to learn knowledge well."