Sonya has 140 beads. how many bags of 10 beads does she need so that she will have 200 beads in all

If Sonya already has 140 beads, she needs 60 beads in order to have a total number of 200 beads. You have to find how many bags (that hold 10 beads) are needed to add up to 60.

140 + 10x = 200

10x = 60

x = 6

Sonya needs 6 bags