Combining "if-let" with "OR" so functions may be executed several times on one value

What I am trying to achieve is to execute functions on a value several times when several conditions are met. In particular say we have two variables a and b.

When a is true the value is transformed by the function associated to a, then when b is true the new value is transformed by the function associated to b.

So when the initial value is 0 and the functions are inc and #(+ 5 %) we can get 0, 1, 5 or 6.

My approach was as following but not succeed

user> (def initial-number 0)
user> (if-let [a true b true] (cond-> initial-number a inc b (#(+ 5 %))))
IllegalArgumentException clojure.core/if-let requires exactly 2 forms in binding vector in user:  clojure.core/if-let (core.clj:1758)
user>