Addition/Subtraction Word Problems with 20

A dog had 17 bones. He ate 8 bones. How many bones does he have left?

When Jane got to the pond, there were 9 ducks. 7 more ducks joined them. How many ducks were at the pond altogether?

There were 10 friends at Adam's house. Some friends left and now there are 4 friends. How many friends left Adam's house?

I have 18 pieces of candy. I gave 11 to my friends. How many pieces of candy do I have left?

There were 5 black cats, 2 orange cats, and 6 white cats. How many cats altogether?

13 students were playing kickball. 7 more students joined the game. How many students were playing altogether?

There were 20 dogs at the dog park. After a while, some left. Now there are 8 dogs. How many dogs left the dog park?

I got 14 scoops of ice cream, but 7 scoops fell off. How many scoops of ice cream do I have now?

Mike scored 10 points the first round. He scored point the second round, too. He ended the game with 20 points. How many points did he get in the second round?

Luna found 6 shells. The next day she found even more. Now she has 17 shells. How many shells did she find on the second day?