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$23 \times 21$ is the same as

$$(20 \times 21) + (3 \times 21)$$

which is the same as

$$((20 \times 20) + (20 \times 1)) + ((3 \times 20) + (3 \times 1))$$

Can you figure out where each of these four products appears in the different methods?

Can you deconstruct $246 \times 34$ in the same way?