Let t = 570 truncated to 1 significant figureand r = 570 rounded to 1 significant figureCalculate r – t.

To solve this problem, we first need to understand what it means to truncate and round to 1 significant figure.

1. Truncating to 1 significant figure: This means we only keep the first non-zero digit from the left and ignore the rest. So, t = 570 truncated to 1 significant figure is t = 500.

2. Rounding to 1 significant figure: This means we keep the first non-zero digit and then look at the next digit to decide whether to round up or down. If the next digit is 5 or more, we round up. If it's less than 5, we round down. So, r = 570 rounded to 1 significant figure is r = 600.

Finally, we subtract t from r to get the answer: r - t = 600 - 500 = 100.