Recap rules when rounding to 10 ,100 and 1000 with different sized numbers - use lesson on My Maths if needed https://app.mymaths.co.uk/71-lesson/rounding-to-10-100
Doubling means x2 or adding the same again.
Some numbers are easy and we will probably know them, others we have to work out through partitioning. Use My Maths lesson to understand how to do this if needed https://app.mymaths.co.uk/131-lesson/doubling-and-halving
Halving is the same as dividing by 2. Go through lesson on My Maths https://app.mymaths.co.uk/131-lesson/doubling-and-halving
Extension task: dice game Instructions: https://nrich.maths.org/10654
Go through how to find the number half-way between 2 others using sheet below.
With an adult, go through how to complete magic squares before completing the ones attached below.