Miriam thinks of a whole number. Rounded to the nearest 10, her number is 750 . Rounded to 1 significant figure, her number is 700 . a) What is the smallest possible number Miriam could be thinking of? b) What is the largest possible number Miriam could be thinking of?

Step 1 ：Find the smallest number that rounds to 750 when rounded to the nearest 10 and rounds to 700 when rounded to 1 significant figure: \( 745 \)

Step 2 ：Find the largest number that rounds to 750 when rounded to the nearest 10 and rounds to 700 when rounded to 1 significant figure: \( 754 \)

Step 3 ：\( \boxed{Smallest: 745, Largest: 754} \)