We have a question: If 100 pieces, each 15 centimeters long, are cut from a 51-meter long ribbon, how much ribbon remains ?
And an answer: 36
So how you got the answer?
The total length cut from the 51 - meter ribbon is 100 x 15 centimeters = 1500 centimeters. Since 1 meter is equal to 100 centimeters, then 1500 centimeters is equal to 1500 / 100 = 15 meters. Therefore, 51 - 15 = 36 meters of ribbon remains.

We have a question: Osborn is testing a new way to get dressed in the morning on school days so he goes faster and can get up later. He tracks his time for the week and on Monday is takes him 2 minutes. On Tuesday it takes him 4 minutes. On Wednesday it takes him 3 minutes. On Thursday it takes him 4 minutes. Before Friday arrives he looks at his old way of getting dressed and sees that it was taking him 3 minutes on average to get dressed. How fast does he have to get dressed on Friday so his weekly average ties his old method?
And an answer: 2
So how you got the answer?
If it takes on average 3 minutes to get dressed, then it takes 15 minutes total on the school week because 5 x 3 = 15. Thus far this week it has taken him 13 minutes to get dressed because 2 + 4 + 3 + 4 = 13. To tie his previous method, he needs to take 2 minutes on Friday because 15 - 13 = 2.

We have a question: Lana aims to sell 20 muffins at the bake sale. She sells 12 muffins in the morning. She sells another 4 in the afternoon. How many more muffins does Lana need to sell to hit her goal?
And an answer: 4
So how you got the answer?
Lana sold 12 muffins and has to sell 20 - 12 = 8 to hit her goal before the bake sale ends. When she sells another 4 in the afternoon Lana has 8 - 4 = 4 muffins left to sell to meet her target.