University:
High School
Course:
High School Mathematics
Academic year:

2022
Views:

231

Pages:

2
Author:

NRussell

Name: ANSWER KEY 2015 Date: Period: And You Think You Have Significant Problems? Significant Figure Rules & Practice Important Ideas Measurements (3.25 cm) are different than numbers (3.14159252). Measurements consist of a number and units. Measurements are an action by someone with a measuring instrument. Measurements have built-in uncertainty, no measurement is exact. PAPER CLIP: 1. Estimate the length of your paperclip using each of the rulers given below... 10 length of paper clip 3 length of paper clip 3.5 om 1 2 a 4 8 7 9 10 11 length of paper clip 3.51 cm 1 2 3 4 5 7 8 9 10 11 LENGTH: 1. In the picture at right, the scale on the ruler reads to the nearest Millimeter. This means that we can reasonably estimate to the hundreths place. Therefore, we might say that the length of this nail is 636cm VOLUME: 2. In the picture at left, the scale on the graduated cylinder reads to the nearest millileter. This means that we can reasonably estimate to the tenthe place. Therefore, we might say that the volume of water shown here is 31.7mL. Significant Figure Rules 1. Numbers other than zero are Always significant! Zeros between significant figures are always significant! Any zero used OfrR the decimal point is significant! 4. Zeros used solely as place holleys (for the decimal point) are NOT significant! 5. When we ADD/SUBTRACT, your answer is rounded to the smallest dead ane 6. When we MULTIPLY/DIVIDE, your answer is rounded to the fewer number of sig 6gs 6 71 PRACTICE PROBLEMS: I. Determine the number of significant figures in each measurement. 6.751 g (4) 0.157 kg (3) 28.0 nm (3) 2500 m (2) g (3) 30.07 g (4) 0.106 cm (3) 0.0067 g (2) 0.0230 cm (3) 26.509 g (5) 54.52 cm³ (4) 0.1209 m (4) 2.690 g (4) 43.07 cm (4) 6352001 g (7) II. Add/Subtract the following, and write your answer with the correct number of significant figures. DON'T FORGET ABOUT UNITS!!!! RULE: When we add/subtract, your answer is rounded to the smallest decimal place. 16.5 cm + 8 cm + 4.37 cm = 28.87 cm → 29 cm 13.25 g + 10.00 g + 9.6 g = 32.85 g → 32.9 g 2.36 m + 3.38 m + 0.355 m + 1.06 m = 7.155 m → 7.16 m 0.0853 g + 0.0547 g + 0.037 g + 0.00387 g = 0.18087 g → 0.181 g 23.27 km - 12.058 km = 11.212 km → 11.21 km 13.57 g - 6.3 g = 7.27 g → 7.3 g 350.0 m - 200 m = 150 m → 150 m 27.68 cm - 14.369 cm = 13.311 cm → 13.31 cm III. Multiply/Divide the following, and write your answer with the correct number of significant figures. PLEASE BE CAREFUL ABOUT YOUR UNITS!!! RULE: When we multiply/divide, your answer is rounded to the fewer # of sig figs. 2.6 cm × 3.78 cm = 9.828 cm² → 9.8 cm² 6.54 m × 0.37 m = 2.4198 m² → 2.4 m² 0.036 m × 0.0002 m = 0.0000072 m² → 0.000007 m² 3.08 km × 5.2 km = 16.016 km² → 16 km² 35 cm² ÷ 0.62 cm = 56.4516129 cm → 56 cm 9 g + 24.2 g = 33.2 g → 33 g 0.8115 dm³ + 2.15 dm³ = 2.9615 dm³ → 3.0 dm³ 40.8 m² ÷ 5.050 m = 8.07920792 m → 8.1 m