Grade five, volume two, new mathematics curriculum, tutor's teaching edition, page 33, what can I do?
70-5=65 (branch) 60 factor 1.5. 13.65
The factor of 30-4 = 26 (ba) 261.2.13.26.
Factor 40- 1=39 (Ben) 39 1.3 13.39.
The greatest common factor of 65.26 and 39 is 13.