18.432 + 5.55 + 19.3 We can notice that the last number in the process of addition is 19.3 | with 1 decimal place value / 3 significant figures | It is better to change all values to 1 decimal place value / 3 significant figures 18.432 → 18.4 5.55 → 5.6 ( 5 rounds up ) 19.3 → 19.3 Let us add: 18.4 + 5.6 + 19.3 = 43.3 If you add the original numbers, you will get 18.432 + 5.55 + 19.3 = 43.282 43.282 ≈ 43.3
