1st Grade Task: Spaghetti Spill

Learning objectives:

Students will:

Determine the unknown whole number in an addition or subtraction equation relating three whole numbers.
Add within 100, including adding a two-digit number and a onedigit 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.

Essential and guiding questions:

Tell me about the numbers and what they mean.

Show me how you subtracted the numbers.

Is there a way you can check to see if your calculations are correct?

Can you use mental math to solve this?

Can you use these numbers in a different way to see if you get the same answer?

Can you show your thinking using a number line, or a part, part, whole diagram?

What if the answer was 21, how would that change things?