On Monday the Pied Piper caught 1000 rats in a city.
On Tuesday he caught 10% fewer rats than on Monday.
On Wednesday he caught 20% more than on Tuesday.
On Thursday he caught 30% fewer than on Wednesday.
On Friday he rested.
How many rats did he catch in total that week?
If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.