Find the value of each expression mentally.

1. Kiran collects baseball caps.

   He has 5.
   He gets some more.
   Now he has 15.
   How many baseball caps did he get?
   Show your thinking using drawings, numbers, or words.

   Equation:

   Equation:

2. Priya collects comic books.
   She gets 3 new comic books.
   Now she has 13.
   How many comic books did she have to start?
   Show your thinking using drawings, numbers, or words.

   Equation:

   Equation:

Mai is finding the unknown number in  .

She says, “I can use what I know about 10 and some ones to help.”

What does Mai mean?

Find the number that makes each equation true.
Show your thinking using drawings, numbers, or words.