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
Materials
Popsicle sticks and rubber bands or base-10 blocks
Paper and pencil for each student
Actions
The teacher should pose the following question to students:
Louis wants to give \$15 to help kids who need school supplies. He also wants to buy a pair of shoes for \$39. If Louis gets \$1 every day for his allowance, how many days will it take him to save enough money for both? Explain how you know.


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