In an up-and-down counting number, the digits increase to a maximum digit and then decrease. This maximum is not the first or last digit. (Example:
2S68S0 is an up-and-down number, but 25587 6 is not.) How many different
4-digit up-and-down numbers have a maximum digit of 6?

Astudent is determining the influence of different types of food on the growth rate of spiders. she feeds one group of spiders two caterpillars twice a week. the other group received similarly-sized beetles twice a week. she records the amount of time required for individuals to reach sexual maturity. her hypothesis is that the spiders feeding on caterpillars will have a faster growth rate because caterpillars have a higher protein content compared to beetles. in this experiment, what is the dependent variable? spiders assigned to different feeding groups. time required to reach sexual maturity number of prey items fed twice a week. growth rates of each group.