Answer:
1) 1.30g
2) 3 sf
3) 5.66 grams
Step-by-step explanation:
1) Significant figure means the amount of figure we are interested in. Note that 0 is insignificant. For example 30 is a one significant figure i. e the only figure of interest is 3.
Given the figure 1.296 g, as we can see, there are initially for figures in the value. This means we are to eliminate one to make it 3. To do that we will remove the 6 at the back by round it up to 1 and add it to the value of 29 preceding it to give 30. The figure will become 1.30 (to 3sf).
Note that only values greater than 4 are rounded up to 1 and added to the preceding value
2) Given the figure 2020, the number of significant figures present is 3 significant figure. Note that all zeros at the end of a value are considered insignificant hence the only significant value here is 202 (which is 3 sig fig.)
3) For the figure 5.658, the value to 3sf is 5.66 (Note that the value of 8 at the end is rounded up to 1 and added to 65 to make it 66). This is as explained in the first answer above.