Look Out! Monsters!

Look Out! Monsters! is a fast paced math game where the object is to score 10 points before losing all your energy.
Your monster is Harry. You control the direction that Harry moves by tapping the arrows. Repeatedly tapping the same arrow makes Harry move faster. The object is to move Harry to the target where the correct answer is shown.
Tapping Go! starts the game, but before you begin use the slider to select a math skill. While playing the game carefully watch Harry's energy level. It it gets too low the game will be over. Remember: Correct answers increase Harry's energy.
Skills:
• Add within 20
• Add within 20.
• Add within 20.
• Add within 20.
• Subtract within 20.
• Subtract within 20.
• Determine the unknown whole number in an addition equation.
• Add within 100, including adding a two-digit number and a one-digit number.
• Given a two digit number mentally find 10 more or 10 less.
• Subtract multiples of 10 in the range 10-90 from multiples of 10 in the range 10-90 (positive or zero differences)
• Fluently add and subtract within 20 using mental strategies.
• Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.
• Add up to four two-digit numbers using strategies based on place value and properties of operations.
• Mentally add 10 or 100 to a given number 100–900, and mentally subtract 10 or 100 from a given number 100–900.
• Fluently multiply within 100.
• Fluently divide within 100.
• Recognize that in a multi-digit whole number, a digit in one place represents ten times what it represents in the place to its right.
• Use parentheses, brackets, or braces in numerical expressions, and evaluate expressions with these symbols.
• Evaluate expressions at specific values of their variables.
• Solve real-world and mathematical problems by writing and solving equations of the form x + p = q and px = q for cases in which p, q and x are all nonnegative rational numbers.