. Which of the following statements are true (T) and which are false (F)? (b) 400 is the predecessor of 399.

That is false because predecessor means a number before a specific number, right now the number is 399 so the number before it is 388 so the answer is false.

That is false because predecesser means one lesser than the number and succesor means one more than the number. 400 is the succesor of 399 not the predecessor. So, the answer is false  

the answer is false because predecessor means one number less than the real number.so 400 is not predecessor of  399

Yes , It is false that 400 is the predecessor of 399.

Because, 

We know that the predecessor of any number n is n-1 .

So , 398 is the predecessor of 399 not 400.