EVERGREEN string question. Combinations and permutations How many strings with seven or more characters can be formed from the letters in EVERGREEN if the two R's are consecutive? I know how to do this if the two R's don't have to be consecutive. Please point me in the right direction.

Okay ill give for 9 letters procreed in same way for 7 ,8.The total letters are $9$ but we want R to be with other so we consider$R+R=1$ so now we have 8 letters so they can be arranged in $\frac{(1+7)!}{4!}=1680$ divided by $4!$ as there are identical 'E'. Total strings of length $7$ are$\frac{7!}{4!}$ but where $R$ is consecutive are $\frac{(1+5)!}{4!}=30$ and fir $8$ total strings are $\frac{8!}{4!}$ but with condition they are $\frac{(1+6)!}{4!}=210$so total ways are $1680+30+210=1920$ . Hope i am clear on this.