1+2+3+4+…… +Is the sum of 1998 + 1999 odd or even? 1 × 2 + 3 × 4 + 5 × 6 + 7 × 8. + 199 × 200 odd or even?

1+2+3+4+…… +Is the sum of 1998 + 1999 odd or even? 1 × 2 + 3 × 4 + 5 × 6 + 7 × 8. + 199 × 200 odd or even?

1+2+3+4+…… +1998+1999
=(1+1999)*1999/2
one million nine hundred and ninety-nine thousand
It's even
1×2+3×4+5×6+7×8.+199×200
=2+12+30+---+39800
All are even numbers, and the result is even

How many times nine equals one

One in nine

1*2+3*4+5*6………… +Is the result of 99 * 100 even or odd? Why?

Even numbers, because even numbers are multiplied by odd numbers

1 / 3 equals 3.3 ·······, 1 / 3 times 3 equals 1, 3.3 ······ times 3 equals 9.9······
Where's 0.00000000 ······ 1?
Is 3.3 ······· multiplied by 3 equal to 1 or 9.9 ········· equal to 1.

Because 1 / 3 is about 0.3333333----------
So 1 / 3 times 3 equals 1
0.333333333 -------- multiply by 3 equals 0.9999999----------

On the math problem. "Think of a number, multiply it by 2, add 8 to the result, divide it by 2, and subtract the number you want. The result is 4." why?
To explain why there are those assumptions, do not say the reason!

Let the number you want be x and the final answer be y, then y = (2x + 8) / 2 - x = x + 4-x = 4

A and B are both natural numbers, and B multiplied by 10 parts of a is less than B, B multiplied by 8 parts of a is greater than B, find the value of A. (write the process)

(a/10)*b

Mo number plus 6 times 6 minus 6 divided by 6, what's the final number of 6

It's equal to one

A and B are both natural numbers, and the value of B multiplied by 10 is less than B, B multiplied by 8, and a is greater than B

BXA/10B
A/101
(because B is a natural number, it is greater than or equal to 0. If B is equal to 0, then BXA / 10 = B (not true), so B is an integer greater than 0.)
eight

If 6 is added to a number, multiplied by 6, subtracted from 6, and finally divided by 6, the result is 6, then the number is______ ．

Let this number be x, then according to the meaning of the question, we can get the equation: {[(x + 6) × 6] - 6} △ 6 = 6, simplify it to x + 5 = 6, and solve it to x = 1

A natural number, the sum of its minimum two factors is 3, the sum of the two maximum factors is 60, what is the natural number?

If the sum of its minimum two factors is 3, then the two factors are 1 and 2, that is, the natural number is a multiple of 2
The sum of the two largest factors is 60. The largest factor must be the natural number itself, and the other largest factor must be half of the number
Therefore, the natural number (1 + 1 / 2) = 3 / 2 is 60, that is, the natural number is 60 / (3 / 2) = 40