One child is the cleanest place to start
For one child, Child Benefit uses the eldest-or-only-child rate. That makes it the simplest example and a useful starting point for understanding the value of the claim in weekly, monthly and annual terms.
It is also the clearest way to compare the value of Child Benefit with other support such as childcare help or council tax support if the household budget is tight.
Two or three children increase the award, but not in a straight line
Once there is more than one child, the first child uses the higher rate and each additional child uses the lower additional-child rate. So the total rises, but it does not simply double or triple in a straight line.
That is why worked examples are useful. They show the real scale of the payment rather than leaving parents to guess from a rate table.
If household income is higher, the next question is HICBC
For some households the more important question is not just how much Child Benefit is paid, but how much is kept after the High Income Child Benefit Charge. That is especially true where one partner has adjusted net income above the threshold.
The practical workflow is simple: check the household Child Benefit amount first, then test the HICBC page if higher income is in the picture.