Is negitive 1.8 greater than negitive 2.1

Unlike positives, with negatives, the larger a number is, the smaller it is.

Example : 
4 > 2

-4 < -2

so -1.8 is GREATER then -2.1

here is a tip :
picture ur number lineplot -2.1any number to the right is greater and any number to the left is less...and since -1.8 is to the right of -2.1, it is greater then -2.1