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

\set_margins 10
%f010
%uDoubles Plus 1%u%n%n

\set_margins 20
%f014
Use this strategy when the addends are neighbors.%n
(8 + 9, 5 + 4, 7 + 8)%n%n

\set_margins 20
%f015
Start with the sum of the doubles and add 1 more.%n%n

%t050 4 + 5 = 9%n
%t050 4 + 4 = 8 and 1 more%n
%t050 9 is 1 more than 4 + 4%n%n%n

%n%n