1. Talgrynnwch y rhifau hyn i'r 10 agosaf ac yna eu hadio gyda'i gilydd.

1. Round the following numbers to the nearest 10 and then add them up:

2. Talgrynnwch y rhifau hyn i'r 100 agosaf ac yna eu hadio gyda'i gilydd.

2. Round the following numbers to the nearest 100 and then add them up:

3. Talgrynnwch y rhifau hyn i'r 1000 agosaf ac yna eu hadio gyda'i gilydd.

3. Round the following numbers to the nearest 1000 and then add them up:

4. Talgrynnwch i'r 1000 agosaf y pellter i Efrog Newydd a Sydney o Lundain.

4. Round up these distances to the nearest 1000 miles and estimate how far New York and Sydney are from London.