The school will reward 242 students with a pen each. They will buy a box of 6 pens at 23 yuan per box and 5 pieces at 21 yuan per box. How to buy the most appropriate pen and how much will it cost at least?

It's only 23 / 6 = 3.83 yuan for each of 6 pieces and 21 / 5 = 4.2 yuan for 5 pieces, so try to buy 6 pieces in a box
242 / 6 = 40 to 2, so that the remainder is the minimum multiple of 5, so it costs 37 * 23 + 4 * 21 = 935 yuan to buy 37 boxes of 6 pieces in a box and 4 boxes of 5 pieces in a box

Listen to the rhythm and write multiplication, Listen to the rhythm and write the multiplication formula. 1. Dingding, Dingding, Dingding, () 2. Ah,) 3. Wuwu, Wuwu, () 4. Meow, meow, meow, ()

3 * 2 1 * 4 3 * 2 2 * 3

Math problem 1. If you sell a dress for 100 yuan, you can earn 25%. The original price of this dress is () yuan 2. For a cylinder and a cone, if the height of both the cylinder and the cone is 10 cm, the radius of the bottom surface of the cylinder is 20 cm, and the radius of the bottom of the cone is 30 cm. The simplest integer ratio of the circumference of the cylinder and the cone ground is (), and the simplest integer ratio of the volume of the cylinder and the cone is () 3. Mother's age this year is three times that of Xiaoying, just 30 years older than Xiaoying. How old are Xiaoying and her mother this year 5. Ming Ming randomly put some go pieces on the go board. Lele found that the ratio of white flag to black chess was just 3:7. Later, Lele changed 8 pieces of black chess into 8 pieces of white flag. At this time, the two kinds of pieces on the board accounted for 50%. How many pieces did Ming put in total?

1.100 × (1 + 25%) = 80 (yuan) 2. The perimeter ratio of the bottom surface is 2 π * 20: (2 π * 30) = 20:30 = 2:3 volume ratio π * 20 * 20 * 10: (1 / 3 * π * 30 * 30 * 10) = 4:33. Xiaoying is x years old, his mother is 3x years old, 3x-x = 30 2x = 30 x = 15 (years old) 3 * 15 = 45 (years old) Xiaoying is 15 years old, mother is 45 years old

There is a bookshelf. The books on the second floor are three times as many as those on the first floor. If you take away 24 books which are exactly the same as the first layer, how many books are there in the two layers?

First floor: 24 × (3-1) = 12 copies
The second floor: 12 × 3 = 36 copies or 12 + 24 = 36 copies
There are 12 + 36 = 48 books on the two shelves

According to the requirements of the school, he arrives at school at 7:30 in the morning. It takes 40 minutes for Xiao Ming to get up every day for breakfast, and 15 minutes for the road,

7:30-(40+15)=6:35
Or, 7:30-40-15 = 6:35

Xiaoming has 30 more sweets than Xiaohong. After Xiaoming gives Xiaohong 25 pieces of sugar, whose sugar is more? Please give the solution and formula!

Xiaoming has 30 more sweets than Xiaohong. After Xiaoming gives Xiaohong 25 pieces of sugar, whose sugar is more? Please give the solution and formula!
The solution is assumed
1. Suppose Xiaohong has 10 candies and Xiaoming has 40
2. After Xiao Ming gives Xiao Hong 25 pieces of sugar, Xiao Hong has 35 pieces of sugar, while Xiao Ming has only 15 pieces
When Xiao Ming gave Xiao Hong 25 yuan, Xiao Hong had more sugar
35-15 = 20 (blocks)
A: Xiaohong has more sugar. 20 yuan more

There's a math problem I don't know how to solve: choose 9 groups of numbers from 1.2.3.4.5.6.7.8.9.10, and each number can only be used once

1+9=10
2+6=8
3+4=7

The eleven numbers 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 form a subtraction formula It's four digits minus three digits to make three digits

657-438=219

In a mathematical problem, nine numbers are selected from 0,1,2,3,4,5,6,7,8,9 to form a three digit addition formula. Each number is used once I need it in a hurry thank you

302+459=761

1234 567 8 requires adding operation symbol to make the formula true

1+ 2 +3+ 4+5- 6 -7+ 8- 9=1

The school will reward 242 students with a pen each. They will buy a box of 6 pens at 23 yuan per box and 5 pieces at 21 yuan per box. How to buy the most appropriate pen and how much will it cost at least?