to advanced skills (e.g., counting by 10s and 100s to 1000, addition/subtraction of two-digit numbers, and word problems involving multiplication/division) (Tzanakak et al.(2014))
cyfrif fesul 10 a 100 hyd at 1000, adio/tynnu rhifau dau ddigid, a phroblemau geiriau sy’n cynnwys lluosi/rhannu) (Tzanakaki et al. (