When multiplying if the tenth place is " 7" then we look " next door" which is the ones and 8 is great then 5 so we count to from 8 to see when the next number ending in 0 would be in this case its 80. ( if the number is 4 or less count backwards to a number ending with 0 which in that case would have been 70 ) but the answer is 80.
