standard_description: Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten.
problem_activity: Task
Chase and his brother like to play basketball.  About a month ago they decided to keep track of how many games they have each won.  As of today, Chase has won 18 out of the 30 games against his brother.
How many games would Chase have to win in a row in order to have a 75% wining record?
How many games would Chase have to win in a row in order to have a 90% winning record?
Is Chase able to reach a 100% winning record?  Explain why or why not.
Suppose that after reaching a winning record of 90% in part (b), Chase had a losing streak.  How many games in a row would Chase have to lose in order to drop down to a winning record below 55% again?


aligns: no