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
Write as many equations for each picture as you can.
Use the numbers 4, 1, and 5.
[IMG]
Here are some equations for this picture. $$4+1=5 \hskip4em 5 = 4+1$$ $$5-1=4 \hskip4em 4=5-1$$ Can you find more equations?
Use the numbers 3, 5, and 8.
[IMG]
Use the numbers 4, 4, and 8.
[IMG]
Use the numbers 4, 5, and 9.
[IMG]
Draw your own picture and write all the equations you can think of to describe it.


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