Answers to mathematics newspaper issue 42

Answers to mathematics newspaper issue 42

On this year's tree planting day, Xiaoming, Xiaogang and Xiaodong participated in the community tree planting activities. The number of trees planted by Xiaoming is 12 times that of Xiaogang and xiaodonghe, and the number of trees planted by Xiaogang is 13 times that of Xiaoming and xiaodonghe. It is known that Xiaodong has 10 trees, and how many trees do Xiaoming and Xiaogang plant respectively?

11 + 2 = 1311 + 3 = 1410 ^ (1-13-14) = 10 ^ 512 = 24 (trees) 24 × 13 = 8 (trees) 24 × 14 = 6 (trees) a: Xiaoming planted 8 trees and Xiaogang planted 6

The sum of a natural number and its reciprocal is 5.2
Don't use equations. I want formulas

Since it is a natural number, its reciprocal must be less than or equal to 1, and only when the natural number is one = 1
So, since the sum of the natural number and its reciprocal is 5.2, then the decimal part of the sum is the reciprocal of the natural number, and the integral part of the sum is the natural number, so the natural number is 5

Y three five, a one, a number can only be used once, the result is equal to 24, how to calculate

5*(5-1/5)=5*(24/5)=24;

There is a rectangular sheet of iron 40 cm in length and 30 cm in width. Cut out an equal small square at its four corners to make a cuboid uncovered sheet iron box 5 cm in depth (the thickness of welding joint is not included). What is the volume of the box?

40-5 × 2 = 30 (CM) 30-5 × 2 = 20 (CM) 30 × 20 × 5 = 3000 (cm3) a: the volume of the tin box is 3000 cubic centimeters

It costs 2700 yuan to buy 10 tables and 60 chairs. The price of three chairs is exactly the same as that of one table. How much is the unit price of tables and chairs?

The price of a chair is x yuan, the price of a table is 3x yuan, 60x + 10 × 3x = 2700, & nbsp; & nbsp; 60x + 30x = 2700, & nbsp; X (60 + 30) = 2700, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 90x = 2700, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 90x △ 90 = 2700 △ 90, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 30, the price of a table: 30 × 3 = 90 yuan. A: the price of a table is 90 yuan, and that of a chair is 30 yuan

How many square meters is one meter? How many hectares is one meter?

1 hectare = 10000 square meters 1 square meter = 0.0001 hectare 1 square kilometer = 1000000 square meters 1 square meter = 0.000001 square meters

Wang Xiaodan has 42 storybooks, (), and how many comic books? 42 divided by (1 minus 1 / 3) condition: () 42 divided by (1 plus 1 / 3) condition:（
Fill in the conditions in brackets, that is, write the title according to the formula, and each question is different

You're in grade six, right? I'm in grade six. The first one is (storybook is one third less than comic book). Since division is used, the unit "1" should be an unknown number. The second one is (comic book is one third more than comic book). It should be like this. The first one I'm sure is the second one. You just have to think about it again. It won't be very difficult

Simplification (27 / 8) ^ - 2 / 3=_______________ .

The original formula = [(3 / 2) & #179;] ^ (- 2 / 3)
=(3/2)^[3*(-2/3)]
=(3/2)^(-2)
=1/(3/2)²
=4/9

Use several scales, a ruler and a pair of scissors to find a way to measure the length of a roll of thin copper wire

First, measure the total mass m of the copper wire with a balance, then measure it with a ruler to 0.1M, cut it off, and then weigh its mass m with a balance, and then use M / m * 0.1, which is the length of the copper wire (unit: m)