Example: 4 and 2
Since there's a 2, you add the 4 two times.
So it'll be like 4*2=8
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If you have one apple plus another five apples you get this | plus | | | | | and so together there is | | | | | | witch equals six all together. Using this mecanism mentaly you could work out any multiplacation (adding/plusing) equasion :]
just build from there.