Explain the place value relationship when the same two digits are next to each other in a multi-digit number.

Take one value as an example, 5664 where there are two digits of '6' next to each other

Partitioning this value, 
5664 = 5000 + 600 + 60 + 4

Notice that one digit of 6 worth 100 and the other worth 10

Take another example, 78869 where there are two digits of '8'

Partitioning this value, we have
78869 = 70000 + 8000 + 800 + 60 + 9

Notice that one digit of '8' worth 8000 and the other worth 800

One other characteristic that we can tell from both example, is that when two same digits are placed next to each other in a value, one digit's value is always worth ten times than the other digit.

for example, the value 600 and 60 from the first example, 600 = 10 × 60