We should always start by writing what we know, especially if we can write it as an equation.
214 = b + g. (214 is boys + girls)
b = g+56 (#of boys = #of girls + 56 more)
214 = g + g + 56 (substitute our equation for boys in order to get only one variable)
214 = 2g + 56 (combine like terms)
158 = 2g (subtract 56 from both sides of the equation to simplify)
79 = g (divide both sides by two in order to solve for girls)
Now we can plug in the value of girls to either of our original two equations and solve for the value of boys.
214 = b + 79
135 = b (subtracted 79 from both sides of equation)
135 boys were in the crowd.
