Answer :

Lets write this out:-

b + b + b + b 

This is the same as b × 4 or a number times 4. To make sure we are correct I will substitute b as 2 and solve. Lets do it:- 

2 × 4 = 8
2 + 2 + 2 + 2 = 8

So, b + b + b + b = b × 4

Hope I helped ya!! xD  
B + B + B + B 

An expression never includes an equal sign. 

b + b = 2b 

2b + 2b 

Answer: 4b