Nine subtract 1.9 equals what.
We could think of the nine digit in 1.9 as nine-tenths. We have to subtract one and nine-tenths from nine. If we add one-tenth to one and nine-tenths, that would give us two. Nine take away two is seven. Now, we just need to adjust our answer. We rounded 1.9 to two by adding one-tenth or 0.1. So we took away 0.1 too much. And now, we need to add it back on. So nine take away 1.9 equals 7.1.
To calculate the answer, first we rounded 1.9 to the nearest whole number, which was two. We subtracted this whole number from nine and then adjusted by adding 0.1 back onto the answer.
Nine subtract 1.9 equals 7.1.