For a three digit number, the sum of the three digits is 13, the number of the hundred digits is 3 less than that of the ten digits, and the number of the one digit number is twice that of the ten digit number For a three digit number, the sum of the three digits is 13, the number of the hundred digits is 3 less than the number of the ten digits, and the number of the one digit number is twice the number of the ten digits Solve by equation

For a three digit number, the sum of the three digits is 13, the number of the hundred digits is 3 less than that of the ten digits, and the number of the one digit number is twice that of the ten digit number For a three digit number, the sum of the three digits is 13, the number of the hundred digits is 3 less than the number of the ten digits, and the number of the one digit number is twice the number of the ten digits Solve by equation

Let the hundreds be x, then the tens be x + 3 and the ones be 2 (x + 3)
X+X+3+2(X+3)=13
4X=4
X=4
This three digit number is 148

If the tens of a three digit number are A-2, the single digit number is two times more than the tens, and the hundred digit number is three times less than the single digit number, then the three digit number can be expressed as?

Ten digit A-2
Single digit 3 (A-2) + 2 = 3a-4
Hundred 3 (A-2) + 2-3 = 3a-7
Three digit 100 (3a-7) + 10 (3a-4) + A-2 = 300a-700 + 30a-40 + A-2 = 331a-742

The sum of a two digit number and a ten digit number is 7, and the new number is 27 less than the original number after exchanging the positions of the two digit number and the ten digit number,
Let the number on the original number of bits be X
It's a linear equation of one variable

Original two digits: 10 (7-x) + x = 70-9x
New double digits: 10x + (7-x) = 9x + 7,
According to the meaning of the title:
70-9X=9X+7+27
18X=36
X=2,
Original double digits: 52