convert 905(base10) to its octal equivalent?

Answer 1

if you're using a windows based computer, the built in calculator does these conversions for you.

Answer 2

keep dividing by 8 and writedown the reminders in reverse order, as you dofor converting to binary
Quotient-Remainder
113 - 1
14-1
1-6
0-1

=> 1611

Or else convertto binary- 1110001001
And groupit into triads starting from rightmost digit
-001-110-001-001 and replace the triads by therir decima(Base10 value)

Thatis
1-6-1-1

Answer 3

905(base10)
=a*8^3+b*8^2+c*8^1+d*8^0
=a*512+b*64+c*8+d*1
=1*512+6*64+1*8+1*1
=1611(base8)