Exercises: addition of natural numbers

$43+22$

First add the 10s.

$40+20=60$

Now add the 1s of the first number.

$60+3=63$

And now the 1s of the second number.

$63+2=65$

$28+53$

First add the 10s.

$20+50=70$

Add the 1s of the first number.

$70+8=78$

To do this, add the 1s of the second number.

$78+3=81$

$17+83$

First add the 10s.

$10+80=90$

Add the 1s of the first number.

$90+7=97$

To do this, add the 1s of the second number.

$97+3=100$