Question

In the number 707B47.B is a prime number.If the number is rounder off to 3sf its value is 708000 what is the biggest value of B

Answer 1

Answer: 7

The list of single digit primes is {2,3,5,7}. The largest prime is 7, so B = 7 is the largest possible value.

Also note how 707,747 rounds to 708,000 when rounding to 3 significant figures.