Math Riddles

Question: If I am buying 9 for $1, 18 for $2, 125 for $3, and 1222 for $4, then what am I buying?

Question: If wanted, use paper!, You may only put 1 line on a number!, how?, thats up to you: 5 + 45 = 450?!.. 883 x 2 = 1776?!.. 282 - 6 x 0 = 288?!..

Question: if Donald trump has 57 dollars and he spends 26 dollars and the cashier guy gives him 36 cents back, how much money does he have?

Question: A pond with dimension of 6m by 3m wil be filled of water lilies at exactly 30 days. Each day the number of water lilies will be doubled. First day 1, second day 2 etc... On what day it will fill half of the pond?

Question: At low tide 14 rungs of a ship are above the water, the rungs are 15 centimeters apart. each 15 mins the water rises 15 centimeters. after 2 hours and 30 mins how many rungs are above the water?