In his phone gallery, Malachi has the number of selfies he took last year and this year in the ratio of 10:17. If he has 2430 photos in his gallery, how many more photos did he take this year than last year?
Let's think: The total ratio representing the number of photos in the Malachi gallery is 10 + 17 = 27. The difference in the ratios representing the number of photos Malachi took this year and last year is 17 - 10 = 7. This year, Malachi took 7 / 27 * 2430 = 630 more photos than he took last year.. The answer is: 630.

In four years, Annika will be three times as old as Hans. If Hans is now 8 years old, how old is Annika now?
Let's think: In four years, Hans will be 8 + 4 = 12 years old. Then Annika will be 12 * 3 = 36 years old. So Annika right now is 36 - 4 = 32 years old.. The answer is: 32.

Joe’s mother gave him $56 to go to the store. Joe bought 7 notebooks and 2 books. Each notebook costs $4 and each book costs $7. How much money does Joe have left?
Let's think: 7 notebooks cost 7 notebooks x $4 / notebook = $28. 2 books cost 2 books x $7 / book = $14. In total Joe has spent $28 + $14 = $42. He has $56 - $42 = $14 left.. The answer is: 14.

Peter needs to buy birdseed to last a week. He knows that each parakeet eats 2 grams a day. His parrots eat 14 grams a day. His finches eat half of what a parakeet eats. If he has 3 parakeets, 2 parrots and 4 finches, how many grams of birdseed does he need to buy?
Let's think:
His parakeets eat 6 grams a day, because three parakeets times two grams each equals 6 grams. His parrots will eat 28 grams a day because two parrots times 14 grams equals 28 grams. Each finch will eat 1 gram a day, because they eat half of what a parakeet does and 1 / 2 of 2 equals one. His finches will eat 4 grams a day because four finches times 1 gram equals 4 grams. His birds eat 38 grams a day because 6 plus 28 plus 4 equals 38. Each week has 7 days. Therefore, in a week he will need 266 grams because 7 times 38 equals 266.. The answer is: 266.