Ffocws rhifedd.
Williams, Helen.
Qualifications, Curriculum & Assessment Authority for Wales.
Bodedern : Gwasg Taf,
2004.
Argraffiad Saesneg gwreiddiol = Original English edition : Oxford : Rigby, 2001.
Addasiad Cymraeg gan Awdurdod Cymwysterau, Cwricwlwm ac Asesu Cymru = Welsh adaptation by Qualifications, Curriculum and Assessment Authority for Wales.
Mathematics
Numeracy