Adding and subtraction problems with the correct number of significant figures
1. 35.2 + 7.89 = 43.09 (rounded to three significant figures)
2. 12.34 - 4.567 = 7.773 (rounded to four significant figures)
3. 456.789 + 123.4 = 580.189 (rounded to three significant figures)
4. 89.23 - 5.67 = 83.56 (rounded to four significant figures)
5. 23.67 + 8.9 = 32.57 (rounded to three significant figures)