When rounding numbers to 1 decimal place, you look at the second decimal place (which is the hundredths place). If the digit in the hundredths place is 5 or greater, you round up the digit in the tenths place. If the digit is less than 5, you keep the digit in the tenths place the same.
Let's round each of these numbers to 1 decimal place:
a) 68.75
The tenths place is 7, and the hundredths place is 5. Since the number in the hundredths place is 5, we round the 7 up by one. So, 68.75 rounded to one decimal place is 68.8.
b) 5.894
Here, the tenths place is 8, and the hundredths place is 9. The hundredths place is greater than 5, so we round up the 8. Therefore, 5.894 rounded to one decimal place is 5.9.
c) 634.9201
The tenths place is 9, and the hundredths place is 2. Since the hundredths place is less than 5, we leave the 9 as is. Thus, 634.9201 rounded to one decimal place is 634.9.
d) 89.99
The tenths place is 9, and the hundredths place is 9. Since the hundredths place is greater than 5, we would normally round up the tenths place. However, 9 cannot be rounded up any further in the tenths place without changing the units digit. In this case, we round up to the nearest whole number, which would make the tenths position a 0. Therefore, 89.99 rounded to one decimal place becomes 90.0.
So the answers are:
a) 68.8
b) 5.9
c) 634.9
d) 90.0
