Nigel measured the mass of a sample of salt it was 3.32 grams. what is its mass rounded to the nearest whole number?

When you are rounding to a whole number, you look at the first number after the decimal point. If the number after the decimal point is 4 and under, then you keep the number in front. If the number after the decimal is 5 and above, then you round the number in front up by 1.
3.32, .32 is less than 5, therefore you keep the same number in front.

3.32 rounded to the nearest whole number would be 3.

Hope this helps!