The number z and −1.9 are additive inverses. drag and drop −1.9 and z to their correct positions on the number line. drag and drop the label “sum” to the sum of −1.9 and z.

Additive inverses are numbers that add up to zero, such as 1 and -1. Z is the additive inverse of -1/9, so z is 1.9.

1.9 + -1.9 =0.

Drag the -1.9 icon to just one mark to the right of -2 on the number line, since each dash equals 0.1.  Drag z to just one mark to the left of 2 on the number line.The sum will be zero, so drag the sum icon to 0 on the number line. 

its a straight line parallel to the time axis

15% chance.

step-by-step explanation:

3/10 times, the 5 year old will get a tablet. 5/10 times, the 13 yer old will get a tablet. multiply both fractions to get 15/100 times, both would have a tablet.