In a place value relationships. The relationship between 2 the same digit place next to each other is the value of the number to left is 10 times bigger than to the value to the left. Let say for example.
1111
1 thousands, 1 hundreds, 1 tens, and 1 ones.
Let’s start from 1 = 1 x 10 = 10
That would be 10 X 10 = 100
then 100 X 10 = 1000
Notice that their value increase base on its place value if we multiply the given number by 10.