Spark PILOT 2017 [Kumon Oak Bay Victoria] Spark PILOT 2017 [Kumon Oak Bay Victoria] | Page 18

S PA R K M a g a z i n e | P I L O T 2 0 1 7
18
KUM O N ST U DI E S
Levels 3A-A
Studying horizontal
addition and subtrac-
tion in 3A 71 to A 200
helps develop students’
mental calculation skills,
which are very useful
when studying verti-
cal addition, subtrac-
tion, multiplication and
division. These skills
can help students prog-
ress smoothly through
higher-level study. The
combination of develop-
ing mental addition and
mental subtraction skills
will prepare students for
the written calculations
in Level B.
Levels B-C
In Levels B and C, we aim for students to solve
the problems without having to write the carries
or borrows. Students who are able to keep the
carries or borrows in their head can develop their
calculation efficiency in higher levels.
Ideally, we should aim for students to solve
vertical addition and subtraction problems without
writing the carries or borrows. Some students will
be able to keep the carries in their head right away.
For other students, this will be a gradual process.
In the beginning, it may be necessary to write the
carried numbers. Once students are able to grasp
the process of vertical addition, we can ask them
to try to keep the carried numbers in their head.
By developing this ability early on, when students
begin studying Level C, they can solve the vertical
multiplication problems without writing carries.
This is also important for the 2-digit-by-2-digit
multiplication in Level D.
In Level B, students
are introduced to
vertical addition
without any
instructions. Students
should use their
mental calculation
skills learned in Levels
3A-A to complete
the vertical addition
problems mentally,
without writing their
carries.
For example, on B 11b
problem (22), students
have to complete
‘13+7’. Students
should complete
these problems using
previously learned
addition. For example,
‘13+7’ can be seen
here on 2A 109a.