At zero, and after you build a score
Multiplying zero still gives zero. Start with additions, then watch for multiplication once you have points. Waiting only for a perfect circle can also waste time.
The same choices in a different order
From 10, +3 followed by ×2 gives 26. ×2 followed by +3 gives 23. There is no route to memorise: the board keeps changing. Look at the order of addition and multiplication before trying to calculate every small number.
In Burning Time, look before tapping
With many red circles, tapping everything is tempting. An accidental division or subtraction can undo earlier gains. Division by 1 does not change the score. In the last few seconds, read the sign before trying to scan every number.
Comparing scores
Each next round brings a different random board. One score does not tell the whole story; practise making choices over several rounds. You can always replay without publishing or opening the ranking.