Dongdong is 12 years old this year, but he has only had three birthdays. He is______ Month______ He was born on the 15th

Dongdong is 12 years old this year, but he has only had three birthdays. He is______ Month______ He was born on the 15th

Dongdong is 12 years old and has three birthdays, 12 △ 3 = 4, which means that he has only one birthday in four years, that is, he was born on February 29 of leap year. A: he was born on February 29. So the answer is: 2, 29

When Xiao Hong was 12 years old, she only had three birthdays. What month and day was her birthday? In what quarter?

February 29th birthday, first quarter
2 and 29 days only appear in leap years. Leap years occur every four years, so 12 years old has only three birthdays
January March is the first quarter

The school bought 135 new books of three kinds, among which children's books are three times of popular science books and story books are one-half of popular science books. How many books did they buy? (2) the school bought 6 volleyball and 8 football, which cost 1028 yuan in total. The price of each volleyball is 26 yuan cheaper than that of each football. How much is each volleyball? How much is each football?

135 / 9 = 1515 * 2 = 3030 * 3 = 90 story books: 15, popular science books: 30, children's books: 90

Use a 50 cm long and 40 cm wide rectangular iron sheet to make a 10 cm deep uncovered cuboid (the thickness of the iron sheet at the welding joint is not included). What is the volume of this cuboid?

(1) As shown in the figure, volume: 10 × (50-10 × 2) × (40-10 × 2) = 10 × 30 × 20 = 6000 (cm3) answer: the volume of this cuboid is 6000 cubic centimeter. (2) volume: 10 × (50-10 × 2) × (40-10 × 2) = 10 × 30 × 20 = 6000 (cm3) answer: the volume of this cuboid is 6000 cubic centimeter

There is a mathematical operation symbol "⊗", so that the following formula holds: 2 ⊗ 4 = 10, 5 ⊗ 3 = 18, 3 ⊗ 5 = 14, 9 ⊗ 7 = 34. Find 7 ⊗ 3=

From the meaning of the title, the meaning of the operation symbol "⊗ B" is a ⊗ B = 3A + B, so 7 ⊗ 3 = 3 × 7 + 3 = 24; answer: 7 ⊗ 3 = 24

0.432 square meters = how many square decimeters and how many square centimeters

0.432 square meters = 43 square decimeters 30 square centimeters
1 square meter = 100 square decimeter = 10000 square centimeter

There are 25% comic books and 35% fairy tale books in the school reading room. There are 320 fewer comic books than fairy tale books
How many books are there in the reading room

320/(35%-25%)=3200
35% x -25%=320
x=3200

The sum of the first four terms of an arithmetic sequence is 24, and the difference between the sum of the first five terms and the sum of the first two terms is 27

a1+a2+a3+a4=4a1+6d=24
5a1+10d-2a1-d=27
a1=3 d=2
an=3+2(n-1)=2n+1

The measurement unit of height in the Three Kingdoms
When introducing a person in the Three Kingdoms, we usually introduce the height of a person. However, if we use the current "inch" to calculate, it is normal to be 3 meters long and 3 meters high (Guan Yu is nine feet, 1 inch = 33.3cm, that is 299.7cm)! So, what was the "inch" at that time? Of course, it is better to make statistics of all the size data you know now! -- thank you very much!

Guan Yu's height, the current size, should be about 2.17 meters
In the Shang Dynasty, one foot is 16.95cm. According to this scale, the height of a person is about one foot, so it is called "husband";
In the Zhou Dynasty, one foot was 23.1cm;
In Qin Dynasty, one foot was about 23.1cm;
In Han Dynasty, one foot was about 21.35-23.75cm;
In the Three Kingdoms, one foot is 24.2cm;
In the Southern Dynasties, one foot was about 25.8 cm;
In the Northern Wei Dynasty, one foot is 30.9cm;
In Sui Dynasty, one foot is 29.6cm;
In Tang Dynasty, one foot is 30.7cm;
In song and Yuan Dynasties, one foot was 31.68cm;
In the Ming and Qing Dynasties, carpentry was 31.1cm

Cat, cat, answers to Feng Zikai's reading questions

1. Stand out, sit upright and look majestic
Make sentences:
He got the first place in the grade with excellent results
2. Expel (second) spine (second) scold (second) satirize (second) burly (first) and happy (second)
3. For special and striking people, they can be called Uncle ironically
4. Last sentence
A pile of cow dung
(2) Sit upright and concentrate on "I've heard so much about you" and "how dare you"
(3) Uncle xiaoshanpo makes trouble