Visa visit permitted for 6months in 12months rules ..can it accumulative in between short trip and enter to visit UK ?

[Mei03]

I am from Malaysia and my passport permitted for 6months visa visit in UK. I would want to go to UK on August ,2018 this year.

Last year I went to visit my brother on 6th February 2017 until 20th March 2017 In between i went to Amsterdam for short trip In 8days. On 20th March I came back in Malaysia.

After 3months later, I went to UK on 10th July until 30th Nov ,2017 and in between also visited Amsterdam in 8days.

Just wondering my last trip Return in Malaysia on 30th (Nov) , 2017. I came back in Malaysia for now counting back coming 8months until August this year already. Would need to ask my previous visited on Feb & March in between the months of (Jan, April , May & Jun) I was back in Malaysia does these months accumulative in 12months rules too?

Which means I accumulative the months i was back in Malaysia on 2017, (Jan, April, May, Jun, & Dec) & 2018 ,(Jan, Feb, March, April, May, Jun , & July ). May I ask am I still able to go to UK on Aug, 2018?

[The Station Agent]

Only the days spent in the UK count. Time outside the UK does not.