Ffocws rhifedd 4 : llyfr ymarfer /
Frobisher, L. J.
Askew, Mike.
Ebbutt, Sheila.
Qualifications, Curriculum & Assessment Authority for Wales.
Caergybi : Gwasg Taf,
2001.
Addasiad Cymraeg gan Awdurdod Cymwysterau, Cwricwlwm ac Asesu Cymru = Welsh adaptation by Qualifications, Curriculum and Assessment Authority for Wales.
Argraffiad Saesneg gwreiddiol = Original English edition : Oxford : Rigby, 1999.
Numeracy