What people are saying - Write a review
We haven't found any reviews in the usual places.
Mental addition 21 Two general remarks about mental
Subtraction by adding up 24 Audit 25
10 other sections not shown
0-factor 100-complement 11-remainders 3-groups 9-packets append the square apply arithmetic auxiliary number boundary-division carry-over column complement-remainder cross-multiplication cross-sum decimal point distance divisibility rules division by 11 division-remainder easier errors of 9 errors of position estimate exactly example Exercises experienced calculator factor-division factorisation factors final remainder formula fraction ft ft given number gives halve Karl Menninger large multiplication table leaves remainder Martin Gardner means mental mental arithmetic method metic multiple of 9 neighbouring nine-test Note number of places number of zeros numbers ending odd number one-digit number order of magnitude original number original value p-ratio p-value partial answer partial remainder particular numbers percentage prime number proof reader remember RULE Add RULE Multiply RULE To multiply rules for divisibility semi-mentally simple squares of numbers stem-fractions stroke surprisingly simply teacher test for divisibility test holds three digits total remainder trick two-digit number U-product unit-boundary whole number write written