That would be 6.
No factor of 9 has three digits. 450 is a three-digit multiple of 150 (and of 9) with a digit sum of 9.
450 or 900
The number whose farthest right significant digit determines it. Whatever place that digit is in is the last significant digit in the sum. For example: 433 + 150 + 3.67 + 8000 = 8586.67, but in sig figs this is only 9000, as the thousands digit is the lowest digit that can be represented.
150 thousands = 150,000
150 thousand thousands.
There are 600 5-digit numbers divisible by 150.
150,000,000 A decimal form simply means that the place value of each digit is ten times that of the digit to its right.