My new maths strategy is going back through a tidy ten. This is how you do it.1
85-14=71 21-14=7
85-5=80 21-1=20
80-9=71 20-13=7
This why i work so i had 85 and i took away 5 then i have 80 now i have to 9 from 80 and i have 71.
what is your maths strategy?