Help with some math problems? 20

This question can be expressed as a good understanding by the following formula:

Divide by 6 = 7......（

6 is the divisor The parentheses after 7 are the remainder, the remainder should be smaller than the divisor, the remainder should be 5 at most, the minimum is 1, the parentheses in front are the dividend, the dividend is equal to 6x7 + 5 = 47 or 6x7 + 1 = 43 So this basket of leaves originally had a minimum of 43 leaves, and a maximum of 47 leaves.

6*7=42, because there are some left, so it won't be 42, but +1=43, so at least 43 pieces.

But not more than 48 leaves, because 6 * 8 = 48, so that each silkworm can get an average of 8 leaves.

So up to 47 leaves.

There are a minimum of 43 leaves and a maximum of 47 leaves.

Estimated 386 + 427 500 - 387 647 + 465 503 + 279 743x7 87x9

Oral arithmetic 26 + 9 = 57 38 1500 700 42 2 99 3 770 7

Check: 26+45 89+22 138-73 674-129 13*31 14*36 1318 12 7842 21 Is it okay?

You're such a good boy, I'll help you out, I hope which one will help you Oral arithmetic: 28+36=

I don't quite understand what the estimate is.

Check 26+85

A passenger car and a freight train at the same time from the two cities A and B are relatively open, it is known that the passenger car travels 55 kilometers per hour, the passenger car travels 10 kilometers more than the freight car per hour, the two cars meet 3 hours after driving, and ask how many kilometers the railway between the two cities A and B is long.

And because the side of the 30-degree angle in the right triangle is equal to half of the hypotenuse, and the adjacent edge is equal to 3 times the opposite side, the side length can be obtained.

ab = 6 cm, ac = 3 3 cm, dc = 3 cm, so ad=2 3 cm, de=2 cm=eb, <>

Solution: Set the height of each floor of the house x meters.

then 9x+4=

9x=x A: The height of each floor of the house is meters.

Solution: Set the height of each floor of the house x meters.

9x+4=solution x=

A: The height of each floor of the house is meters.

The first, 4 3 = 12, 12-4 = 8

Second, 5 5 = 25, 25-8 = 17

In this way, the law comes out, the product of the following two numbers, and then subtract the middle number, which is the number at the top.

In this way, the third, 4 4-4 = 12

Fourth, 3 5-10 = 5

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Satisfied, please promptly. Thank you!

The product of the bottom 2 numbers minus the middle number is the upper number.

So the answer is: 12 5

I was stunned as a junior high school student.

Question 1 Set up x peach trees and y apricot trees, according to the title.

x-y=40

y=80%x

It follows from this. x=200

y=160A: There are 200 peach trees and 160 apricot trees.

Question 2: The number of people in the first class of six years is x, and the number of people in the second class of six years is y.

x-y=15

x-y）/x=30%

From this keybook.

x=50y=35

Answer: The number of students in the first class of the sixth year is 50, and the number of people in the second class of the sixth year is 35.