Although the head of the decimal point is small, I know that the decimal point is not small. For example, 3.80 yuan, without a decimal point, doesn't it become 380 yuan? 3.80 yuan is too different from 380 yuan! Don't you see how big the decimal point is in this comparison?

Many students often miss it when writing, so this number is not what you originally wanted to write. So let's not make this big mistake again!

extreme

Reading popular science books at home, I saw a sentence: "People grow taller every day, but they don't realize it, because people only grow taller by 0. 1~0.2 mm every day." After reading it, I thought: If I grow 0.2 mm every day, how tall will I be at the age of 20? Thinking of this, I immediately began to calculate: it is 2005, I am 1 1 years old, and there are still 9 years before I turn 20. 2005+9=20 14 (year) has 365 days every year, in which 2008 and 20 12 are leap years, which need two days, 365×9=3285 (days) 3285+2=3287 (days) 3287× 0. 145=65.74=2 10.74 (cm). If it is not a decimal, my height will be as high as 2 meters 10 cm. If I really grow 0.2 mm every day, then I am too tall at the age of 20!

Tisso

Tonight, my cousin and I are playing on the playground. We found a square waste paper board with an area of about one square meter near the playground. My cousin looked at it and said, "Xiao Jing, if you divide this cardboard into small squares with an area of one square millimeter, and then connect these small squares one by one into a straight line, how long is this straight line?" I blurted out without thinking, "How long can this last? Four meters at most! " Cousin smiled and said, "Don't jump to conclusions yet, let's work it out together." I straightened my back and began to think for a while: 1 square meter equals100000 square decimeter, and the side length of a square with 1000000 square millimeter is 1000000 mm, so isn't it the same with 1000000 mm? Wow! This straight line, which consists of some small squares of one square millimeter, is as long as 100 meter.

Article 4

Today, I came across such incredible data in a book: "A piece of paper with a thickness of 0.0 1 cm is thicker than Mount Everest after being folded in half for 30 times?" This data is a bit "absurd" no matter how you listen to it. After all, it is a thin piece of paper. Can folding in half really surpass Everest? But many unexpected things may happen, so only through calculation can we uncover the mystery of all this.

Immediately I multiplied 0.0 1 cm by 2,1* * 30 times to get10737418.24cm.. Then, I converted the height of Mount Everest from 8848. 13 m to 8848 13 cm. By comparison, it is obvious that the thickness of paper folded in half for 30 times is indeed better than the height of Mount Everest, which is more than 10 times of the latter.

chapter five

"Dad, what's so happy today?" Dad said, "I got a raise this month." I asked, "How much salary do you get now?" Dad thought for a moment, smiled and said, "My salary is higher than your mother's. Our monthly salary adds up to 2800, and the monthly salary difference is 100. How much do you think I get a month? " First of all, mom's salary is as much as dad's, so mom and dad's monthly salary is (2800+ 100)=2900 yuan, and then the total monthly salary is divided into two parts, and 1 part is dad's monthly salary. The formula is: (2800+ 100)÷2= 1450 yuan. Dad said: Great!