The sum of a two digit single digit and a ten digit number is 10, if the single digit number is comb

Solution: Let the single digit be x, then the ten digit is (10-x) According to the title, the original two-digit number is.

10（10-x）+x=100-9x

After conversion, the two-digit 10x+10-x=9x+10 is subtracted to 18x-90=18 to get x=6

The original two-digit number is 46

Solution: Let the single digit number be x, because the ten digits + x = 10, and the single digit and the ten digit number are swapped, and the new two-digit number obtained is 18 larger than the original two-digit number, so the ten-digit number is less than 5 (if 5, then after the exchange of positions, the new two-digit number is smaller than the original two-digit number), greater than 3 (if it is less than or equal to 3, then after the exchange of positions, the difference between the new two-digit number and the original two-digit number is much more than 18, at least equal to 73-37=36), so, x=4, this two-digit number is 46, After swapping it is 64, after swapping places, the difference between the new two-digit number and the original two-digit number is 64-46=18

Let the single digit be a and the number ten be b, then there is:

2.(10a+b)-(10b+a)=18

The solution is a=1 b=9

Here's some digital common sense.

The difference between two digits is 18, and the single digit plus ten digits equals 10

Then the two number changes are 46 and 64

This can be proven.

Let the single digit be x and the ten digit be 10-x

It turned out to be 10 (10-x) + x

The inversion is 10x+ (10-x).

So 10 (10-x) + x = 10x + (10-x) + 36100-9x = 9x + 46

18x=54

x=3A: The original number is 73

This digit xy

x+y=10

10x+y-36=10y+x

x=7y=3

This two-digit number is 73

If the single digit is x, then the ten digit is 10-x

This two-digit number is.

x+10(10-x)=100-9x

Let the single digit of this number be x, then the number of ten pure letters is (8-x), and this number is 10 (8-x) + x = 80-9xAfter swapping, it is 10x+(8-x)=9x+8

80-9x）（9x+8）=1855

81x²+648x+640=1855

81x²+648x-1215=0

9x²-72x+135=0

x²-8x+15=0

x-3）（x-5）=0

x=3 or x=5

This two-digit number is 35 or 53

The tens and single digits are x, y, respectively

x+y=12

10y+x)=4/7(10x+y)

x=8,y=4

The original number was 84

It turned out x pcs. 120/x-120/（1+1/4）x=3x=8

1.Let the ten digits and the single digits be x and y, respectively

So x+y=12

10y+x)=4/7(10x+y)

So x=8y=4, so the original number is 84

2.Set the original x person.

120/x-120/（1+1/4）x=3

So x=8

1.Let this ten digit be ax10+b, then the equation can be as follows:

a+b=12

bx10+a=4/7（ax10+b）

Solve the system of equations, a=8, b=4

So, the original two-digit number was 84

2.If there are x people in the group, and each person pays y yuan, then the equation can be listed:

xy=120

x+1/4x)x（y-3）=120

Solve the equation and get.

x=8 y=15

So, it turned out that there were 8 students in this group.

Let the number of hundreds and the number of single digits be obtained according to the meaning of the question: a+b=12 and a=b-2, and the solution is a=5, b=7, so the original number is 507

Let the original two tens of digits be x and the single digits be y

Then x + y = 12

10x+y)*4 7 = 10y+x i.e. 40x + 4y = 70y + 7x i.e. 33x - 66y=0 i.e. x - 2y = 0

So x= 8 , y = 4

It turned out that the two-digit number was 84

Middle School Mathematics, Physics and Chemistry Solution Group].

Let the single digit of this two-digit number be x, then the ten digit is 11-x, which can be expressed as: 10 (11-x) + x = 110-9x

The modulated number can be expressed as: 10x+11-x=9x+119x+11=110-9x+63

9x+9x=110+63-11

18x=162

x=162÷18

x=911-x=11-9=2

It turned out that the two-digit number was 29

Let the number of tens be x

The single digit is 11-x

10 times (11-x)+x - (10x+11-x)=63

Let the original number of disturbance be 10x+y, and 10y+x after Li Chunhou, according to the title: auspicious.

x+y=11

10x+y+10y+x=121

Solution; x=2,3,4,5,6,7,8,9

y=9,8,7,6,5,4,3,2