\set_margins 12
%f011
%uAddition%u%n%n

\set_margins 10
%f010
%uAdding 9's%u%n%n

\set_margins 20
%f015
Children easily add 10 to a number. They quickly solve
 problems like 35 + 10 = 45. Learning this trick helps
 children tackle the more challenging task of adding 9 to a
 number: Adding 9 to a number is the same as adding 10 and
 then taking 1 away.%n%n

%t050 67 +  9 =  ?%n
%t050 67 + 10 = 77%n
%t050 77 -  1 = 76%n
%t050 So 67 + 9 = 76.%n%n

\set_margins 20
%f014
Apply a similar strategy when adding 11 to a number%n
(add 10, then add 1 more) or when subtracting 9 from a number%n
(subtract 10, then add 1).%n%n

%n%n