Problem
As the box runs 0-9, C ranges 70.002 to 70.092, B ranges 70.096 to 79.096, A ranges 79.098 to 79.998.
Plugging in the smallest and largest digit shows the whole span each number can cover.
5.NBT.A.3Make A Systematic ListC's max (70.092) is below B's min (70.096), so every C is less than every B.
If C can never reach as high as B's lowest, C is always smaller.
4.NF.C.7Guess And CheckNo matter which digits fill the boxes, label C is always less than label B.
C reaches its greatest value 70.092 only when its box holds 9, B reaches its least value 70.096 only when its box holds 0, and 70.092 is already below 70.096 — so even C at its highest cannot reach B at its lowest.
Raising the digit in one place adds more of that place's value, so a box gives its number the biggest total at 9 and the smallest total at 0.
A digit tells how many units sit in its place, and each place is worth ten of the place to its right, so more units in a place means a larger number.
Lining 70.092 and 70.096 up by place, every digit matches until the thousandths, where 2 is fewer than 6, so 70.092 is the smaller number.
Because each place is worth ten of the next, a difference in a higher place outweighs everything below it, so the first place where two decimals differ decides which is larger.
B's max (79.096) is below A's min (79.098), so every B is less than every A.
B tops out just below A's floor, so B is always smaller than A.
4.NF.C.7Guess And CheckFind the lowest and highest each number can be - if the ranges don't overlap, the order is locked in!