ABCD stands for a 4-digit number. He multiplies 4 = DCBA to find ABCD

2178a can only be 1 or 2, otherwise the product is more than 4 bits. But it is impossible to have 1 at the end of 4 * (), so a = 2 D = 8 (3 is impossible, 2 () * 4 is at least 8 () ()), then B can only be 0 or 1, but c * 4 + 3 cannot have 0 at the end (c * 4 is impossible to have 7 at the end), so C = 2 or 7 of B = 1 because a = 2

Ask 925 pure silver and 999 thousand foot silver which is good?

Verification: 10 can be divisible (n ^ 1999-n ^ 999), where n is a natural number

Because the single digit of an integer power is four times a cycle (or two digits)
1999 / 4 = 499 + 1
999 / 4 = 249 + 1
The 1999 power of n is the same as the 999 power of n
They subtract one to zero
A number whose bit is 0 must be divisible by 10

In the 1000 natural numbers of 1, 2, 3.9991000, how many numbers can't be divisible by 2 or 3

1000/2=500
1000 / 3 = 333 + 1
1000 / 6 = 166 + 4
That is to say, 500 of 1-1000 can be divided by 2
There are 333 divisible by three
That is, 166 can be divided by 2 and 3
Therefore, those that cannot be divisible by 2 or 3 are as follows:
1000-500-333 + 166 = 333

Can 9993-999 be divisible by 998? Can it be divisible by 1 & nbsp; 000? Why?

∵ the original formula = 999 (9992-1) = 999 × (999 + 1) (999-1) = 999 × 1000 × 998, ∵ 9993-999 can be divided by 1000

Using MATLAB to find the number of numbers that can be divided by 21, and to establish a string vector and delete capital letters

clc;clear;
m=0;
for n=100:999
if n/21==round(n/21)
m=m+1;
k(m)=n;
else
end
end
k,m
Results of operation:
k =
Columns 1 through 17
105 126 147 168 189 210 231 252 273 294 315 336 357 378 399 420 441
Columns 18 through 34
462 483 504 525 546 567 588 609 630 651 672 693 714 735 756 777 798
Columns 35 through 43
819 840 861 882 903 924 945 966 987
m =
forty-three

How much is 123 degrees 2 minutes 5 seconds minus 92 degrees 24 minutes 48 seconds?

1°=60′,1′=60″
The result is 30 degrees 37 minutes 17 seconds

What's the difference between the product of 36 and 18 minus the product of 24 and 16

Hello
The product of 36 and 18: 36 × 18
The product of 24 and 16: 24 × 16
The difference between them: 36 × 18-24 × 16 = 648-384 = 264
If you don't understand, you can ask
I wish you progress in your study!

24 times () minus () times 15 = 18

24*（2）-（2）*15=18

How to calculate 625-477-123 + 275

625-477-123+275
=(625+275)-(477+123)
=900-600
=300

ABCD stands for a 4-digit number. He multiplies 4 = DCBA to find ABCD