Answer:
The symbol that represents IIII in base ten is the numeral 4 (IV represents the numeral 4 in Roman numerals, not IIII).
In base ten, each digit represents a power of ten. The rightmost digit is the units place, followed by the tens place, hundreds place, and so on.
For example, in the number 456, the digit 6 represents 6 units, the digit 5 represents 5 tens, and the digit 4 represents 4 hundreds.
In the case of IIII, it represents 4 units.
So, to represent IIII in base ten, we simply use the numeral