Grade 1 Addition through Subtraction

[Mary Ellen]

At Grade 1, Standard 1.NBT.4 introduces two-digit addition: “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  . . . .”

How would you use “the relationship between addition and subtraction” to introduce addition? Subtraction of two-digit numbers is introduced in a later standard, 1.NBT.6.

 

[Jim]

It is “a later standard” in the since that it occurs after this standard in the document.  However, they are both Grade 1 standards and can therefore be taught in whatever order is deemed appropriate.

[Bill McCallum]

Thanks Jim, that’s exactly correct, and let me take this opportunity to remind everybody that the order of the standards does not dictate the order in which they are taught (see page 5 of the standards). In particular, a thoughtful curriculum will probably intertwine the OA and NBT standards in any given grade. The OA domain is intended to highlight work on number and operations that serves to prepare students for algebra. But this work goes hand in hand with the work on the base ten system and computation with the operations in NBT.

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