How do I determine what my deduction for Qualified Business Income is for AGI periods?

[5haughtons]

I am annualizing my income to avoid a penalty. TT asks me to:  "Enter your deduction for qualified business income for each period".  How do I figure what it is for each period?

[MinhT1]

The QBI deduction for each period is proportional to the Qualified Business Income that you have allocated for each period.