Bar Model — 1 + 2 = 3 — free printable diagram

What is 1 + 2?

This part-whole bar model shows 1 and 2 as the two parts of one whole. Adding the parts gives the whole, so 1 + 2 = 3.

First part

1

Second part

2

Whole

3

Addition

1 + 2 = 3

Subtraction

3 − 1 = 2

• A part-whole bar model shows the whole on one bar and the parts that make it on the bar underneath. Here the two parts are 1 and 2, and together they fill the whole bar of 3.
• The parts can be added in either order — swapping them does not change the whole: 1 + 2 = 2 + 1 = 3.
• Covering up one part turns the same picture into a subtraction: 3 − 1 = 2 and 3 − 2 = 1.
• That is the fact family for these three numbers — the model is the reason 1, 2 and 3 belong together, whichever way round you write them.