TY  - BOOK
AU  - Ashlock,Robert B.
TI  - Error patterns in computation: a semi-programmed approach
AV  - QA135.5 .A782 1986
U1  - 372.7/2044 19
PY  - 1982///
CY  - Columbus [Ohio]
PB  - Merrill Pub. Co.
KW  - Arithmetic
KW  - Study and teaching (Elementary)
KW  - Local
N1  - Bibliography: p. 161-178
ER  -