# Integration is just a better multiplication

Regular readers know that I am a big fan of *Better Explained* in which Kalid makes mathematical ideas accessible*.*

Integration is just multiplication when one of the operands is changing.

Most people grok integration as *area under a curve* but, as Kalid explains, *area* is just one convenient way of visualizing multiplication…but we don’t need to visualize multiplication as multiplication is already pretty straightforward – in the simplest case, it’s just repeated addition.

Many ideas in maths start out simple like that and then gradually generalize to a more complex idea. In Kalid’s words:

Our understanding of multiplication changed over time:

- With integers (3 Ã— 4), multiplication is
repeated addition- With real numbers (3.12 x sqrt(2)), multiplication is
scaling- With negative numbers (-2.3 * 4.3), multiplication is
flippingand scaling- With complex numbers (3 * 3i), multiplication is
rotatingand scalingWeâ€™re evolving towards a general notion of â€œapplyingâ€ one number to another, and the properties we apply (repeated counting, scaling, flipping or rotating) can vary. Integration is another step along this path.

In other words,

Integration is just a better multiplication

or, conversely,

Multiplication is a special case of integration when the values are static.

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