Question about 3.OA.3

[msg11245]

I have a question about 3rd grade multiplication. 3.OA.3 says

Use multiplication and division within 100 to solve word problems in
situations involving equal groups, arrays, and measurement quantities,
e.g., by using drawings and equations with a symbol for the unknown
number to represent the problem.

3.OA.5 says

Apply properties of operations as strategies to multiply and
divide.2 Examples: If 6 × 4 = 24 is known, then 4 × 6 = 24 is also known.
(Commutative property of multiplication.) 3 × 5 × 2 can be found by 3
× 5 = 15, then 15 × 2 = 30, or by 5 × 2 = 10, then 3 × 10 = 30. (Associative
property of multiplication.) Knowing that 8 × 5 = 40 and 8 × 2 = 16, one
can find 8 × 7 as 8 × (5 + 2) = (8 × 5) + (8 × 2) = 40 + 16 = 56. (Distributive
property.)

Because of this example, 3 × 5 × 2 can be found by 3 × 5 = 15, then 15 × 2 = 30, or by 5 × 2 = 10, then 3 × 10 = 30, we have many 3rd grade teachers in our district are interpret this to mean that when they are solving problems in 3.OA.3 that they can do any type of problem 1-digit x 1-digit or 2-digit x 1-digit as long as the product is less than 100. They are further taking this to mean they need to teach students how multiply 2-digit x 1- digit numbers.

How far are 3rd grade teachers to take multiplication? Are they to focus on the 1-digit x 1- digit as specifically stated in 3.OA.7?

[Bill McCallum]

I think 3.OA.7 is pretty clear on this point:

3.OA.7. Fluently multiply and divide within 100, using strategies such as the relationship between multiplication and division (e.g., knowing that 8 × 5 = 40, one knows 40 ÷ 5 = 8) or properties of operations. By the end of Grade 3, know from memory all products of two one-digit numbers.

It’s true that 3.OA.7 has an additional focus on knowing one digit by one digit products from memory, but “fluently multiply and divide within 100” includes one digit by two digit products less than 100.

[msg11245]

Thank you for clarifying this. My fear is that we will have students within our district who haven’t seen a 2 x 1-digit multiplication.

[Bill McCallum]

Yes, there is certainly an adjustment period during which students will be entering classes with having had a curriculum based on the Common Core in the previous grade. One hopes that teachers will be allowed to apply their common sense.

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