MK_BINOP : term -> thm * thm -> thm
# let th1 = NUM_REDUCE_CONV `2 * 2`
and th2 = NUM_REDUCE_CONV `2 EXP 2`;;
val th1 : thm = |- 2 * 2 = 4
val th2 : thm = |- 2 EXP 2 = 4
# MK_BINOP `(+):num->num->num` (th1,th2);;
val it : thm = |- 2 * 2 + 2 EXP 2 = 4 + 4