A number j minus 14 is less than −21.

If you are supposed to write the inequality, it would be
j - 14 < -21
j represents the number j
minus 14 is taking away or subtracting 14
together, they are less than -21, which is why < is used

A number j minus 14 is less than −21
j - 14 < -21

if you need to find j then
j - 14  < -21
  +14   +14
j < -7

hope it helps