Rocket arrives at the Numbers Desk with a list. "Repeated hops are everywhere once you look."
"The thermometer dropped 2 degrees an hour all evening. Our stair timer takes 3 seconds off for every skipped step."
"A diver at the pool goes down half a meter every second," he adds. "That is 0.5 × (-1) each second."
Raven reads the list. "What do you notice about every one of them?"
"Something negative, repeated," Rocket says. "A hop to the left, over and over."
Nova brightens. "And dividing tells you the size of one hop," she says.
"Then let us review every rule," Raven says. "Next week the seedlings start growing, and that is a different pattern."
A thermometer dropping 2 degrees each hour for 5 hours changes by 5 × (-2) = -10 degrees.
A stair timer that takes 3 seconds off for each skipped step: 4 skipped steps is 4 × (-3) = -12 seconds.
A diver going down 0.5 meters each second is at 6 × (-0.5) = -3 meters after 6 seconds.
And division works backward. A total change of -18 over 6 equal steps is -18 ÷ 6 = -3 per step.
A negative divided by a negative asks how many hops: -18 ÷ (-3) = 6 hops.
| Statement | True or false? |
|---|---|
| A negative number times a negative number is negative. | ? |
| (-3) × (-3) = 9 | ? |
| -18 ÷ 6 = -3 | ? |
| The decimal for 1/8 repeats forever. | ? |
| 4 + 3 × (-2) = -2 | ? |
Terrific week. All four operations with signed numbers are yours. Tomorrow is Data Day with a family toss tournament.