First, we need to work on place values;

If we expand this out, we get

25=20+5

Let's write this another way...  Up and down...

20+5=

We can add these by making stripes and adding straight down!

20+5=

Here's a bigger number:

783

Expand it out:

783=700+80+3

Stack the numbers in your stripes and add straight down:

700+80+3=783 Line up the hundreds in the first stripe...

Line up the tens in the second stripe...

And line up the ones in the third stripe!

Easy!

1 2
of 2