Given that 346 × 27 = 9342 , work out 34.6 × 2.7

Lets compare the numbers in the question:
34.6 x 2.7 is the same as  346/10 x 27/10    (decimal to fraction)
 
therefore...
34.6 x 2.7 is the same as ( 346 x 27 ) /100  (multiplying top & bottom)
 
so if
 346 × 27 = 9342   then    ( 346 x 27 ) /100 = 9342 /100
                                      = 93.42
(whatever we do to the left of an equation, we must also do to the right).
 
A quicker way to solve this problem is to know that if we move the decimal point [ x number of times ] on the left-hand-side of the equation, we must also move it [ x number of times ] on the right-hand-side.