Answer:
500
Step-by-step explanation:
Mental calculation often makes use of factoring and cancelling of factors. To the greatest possible extent, multiplying or dividing by powers of 2, 5 and 10 are also used.
[tex]\dfrac{110568}{220}-\dfrac{568}{220}=\dfrac{110568-568}{220}=\dfrac{110000}{220}\\\\=\dfrac{110}{220}\cdot1000=\dfrac{1}{2}\cdot1000=\boxed{500}[/tex]
