My hundreds digit is 4. when you add my digits, it is 13. my ones digit is twice my tens digit. what number am i?

Out of $20$ creepy-crawly creatures in a room, $80\%$ are flies and $20\%$ are spiders. if $s\%$ of the total legs belong to spiders, what is $s$?

Scores on the cognitive scale of the bayley-scales of infant and toddler development range from 1 to 19, with a standard deviation of 3. calculate the margin of error in estimating the true mean cognitive scale score, with 99% confidence, if there are 12 infants and toddlers in a sample.

In the sixth grade 13 out of 20 students have a dog if there are 152 sixth grade students how many of them have a dog