2 3 4 5 6 7 8 9 10
+2 +3 +4 +5 +6 +7 +8 +9 +10
Here the addends are equal and easily added. The figures should be
placed as above and not 2 + 2, 3 + 3, etc., because the vertical
form is the natural one which the child will use all through life.
It does not look so formal and represents better what he really does
with the objects.