840/1575
Since 840 ends with a 0 and 1575 ends with a 5, they can
both be divided by 5, 840÷5=168 and 1575÷5=315.
So the fraction is now reduced to 168/315
168 has sum of digits 15 and 315 has sum of digits 9, so they are
both divisible by 3, 168÷3=56 and 315÷3=105.
So the fraction is now reduced to 56/105
We know from our multiplication facts that 7×8=56. 105 is not even, so
there's no use to try 8, so let's try to see if 105 is divisible by 7
Yes it is. 56÷7=8 and 105÷7=15.
So the fraction is 8/15, and that cannot be reduced further.
Answer: 8/15
Edwin
