The sum of 100 continuous natural numbers is 8250. Remove the odd number (the first. The 99th) in the 100 numbers, and the sum of 50 numbers is left

The sum of 100 continuous natural numbers is 8250. Remove the odd number (the first. The 99th) in the 100 numbers, and the sum of 50 numbers is left

The number of the even number is one more than that of the preceding one,
The even number of 50 is 50 more than the odd number of 50,
Then the remaining 50 numbers are (8250 + 50) △ 2 = 4150

There are 100 consecutive natural numbers, the sum of which is 8450. Take out the first, second and 99th (all odd numbers) and add these 50 numbers. What is the sum?

1+2+3+… +99+100=（1+100）+（2+99）+… +（50+51）=101×50=1050
8450-1050=3400=34×100
So, these 100 continuous natural numbers are 35, 36, 37, 38 ,133,134
Odd sum is 35 + 37 + 39 + +131+133
=（34+1）+（34+3）+（34+5）+… +（34+97）+（34+99）
=34×50+1+3+5+… +97+99
=1700+（1+99）+（3+97）+… +（49+51）
=1700+100×25
=1700+2500
=4200
Or simply (8450-50) △ 2 = 4200

One to 100 natural numbers add up to 8450. Take out all the singular numbers, and then add these 50 numbers. What's the sum?

That's 8450-50 = 8400 / 2 = 4200

Rearrange the order of the 99 natural numbers from 1 to 99, and add 1, 2, 3 to each number in the new order 99. Is the product of 99 numbers odd or even?

There are 50 odd numbers and 49 even numbers in 99, each even number plus an odd number, and each odd number plus an even number. So there are 98 pairs, (odd + even), but the last pair must be (odd + odd). In the product, if a factor is even, their product must be even, and the result is still even

The sum of two adjacent natural numbers is 97______ And______ ．

(97-1) △ 2, = 96 △ 2, = 48; 48 + 1 = 49; answer: these two natural numbers are 48 and 49

The sum of two adjacent natural numbers is 97______ And______ ．

(97-1) △ 2, = 96 △ 2, = 48; 48 + 1 = 49; answer: these two natural numbers are 48 and 49

5 out of 8 is 1 and 1 out of 4 smaller than a certain number
To list. Equations

Five in eight is one and one in four smaller than a certain number
This number = 5 / 8 + 1 and 1 / 4
=5 / 8 + 10 / 8
=15 out of 8

Five eighths of a number is 81 more than two fifths of a number. What's the number?

5/8 X - 2/5 X = 81
The solution is x = 360

The numerical value is compared with the__ The number of equal numbers on the circle. (1) "24 / 6" 3 / 1 4 / 1 36 / 9 36 / 12 12 / 3 48 / 8 48 / 1
（2） "(3 / 9)" 2 / 6 1 / 12 6 / 12 4

（1） "6 of 24" 1 of 3 4 of 1 36 of 9 36 of 12 12 of 3 48 of 8 48 of 1
6/24=1/4
1/3=1/3
1/4=1/3
9/36=1/4
12/36=1/3
3/12=1/4
8/48=1/6
1/48=1/48
So 1,4,6 are equal; 2,3,5 are equal
（2） "(3 / 9)" 2 / 6 15 / 9 15 / 5 6 / 1 12 / 6 12 / 4
3/9=1/3
2/6=1/3
9/15=3/5
1/6=1/6
6/12=1/2
4/12=1/3
So 1,2,6 are equal

Five eighths of a number is five twelfth. What's the number

5 / 8 of a number is 5 / 12. This number is 5 / 12 △ 5 / 8 = 2 / 3