Third Grade Math for Parents
Overview
Third grade math is all about multiplication. We want students to apply their multiplication skills to story problems, as well as connect the multiplication facts to one another. For example, if a child knows their “times fours”, that can be used to help recall or figure out their “times eights”: Since 3 × 4 = 12, then 3 × 8 must be twice that or 24. This and other strategies will be discussed so the kids who notice these kinds of patterns learn to not just see it but describe what and why. Kids will see and use pictures explaining these connections; pictures that are used again and again through Algebra where they’ll use the same picture to factor quadratic equations!
Students will also do multiplication and division together more, rather than seeing them separately. So, for example, soon after students learn that 4 × 6 = 24 they’ll learn it also means that 24÷4 = 6 and 24÷6 = 4.
Kids will be mastering addition and subtraction in the hundreds. This will mean not only learning the standard way, but figuring out short cuts and alternate approaches and talking about why they work. For many reasons we’d like to see kids see an addition such as 398 + 15 and not have to “line it up” to add but instead say, “well, if we give two of the 15 to the 398 that makes 400 so the answer is 413” or “if we look on the number line, only two steps are needed to get to 400, and then 13 steps more would be 413.
Third grade math is all about multiplication. We want students to apply their multiplication skills to story problems, as well as connect the multiplication facts to one another. For example, if a child knows their “times fours”, that can be used to help recall or figure out their “times eights”: Since 3 × 4 = 12, then 3 × 8 must be twice that or 24. This and other strategies will be discussed so the kids who notice these kinds of patterns learn to not just see it but describe what and why. Kids will see and use pictures explaining these connections; pictures that are used again and again through Algebra where they’ll use the same picture to factor quadratic equations!
Students will also do multiplication and division together more, rather than seeing them separately. So, for example, soon after students learn that 4 × 6 = 24 they’ll learn it also means that 24÷4 = 6 and 24÷6 = 4.
Kids will be mastering addition and subtraction in the hundreds. This will mean not only learning the standard way, but figuring out short cuts and alternate approaches and talking about why they work. For many reasons we’d like to see kids see an addition such as 398 + 15 and not have to “line it up” to add but instead say, “well, if we give two of the 15 to the 398 that makes 400 so the answer is 413” or “if we look on the number line, only two steps are needed to get to 400, and then 13 steps more would be 413.
General parent tips for supporting 3rd grade math
- If you practice multiplication facts, try to highlight related facts especially when your child cannot recall one. For example, if they don’t remember 6 × 6 right away, you can ask “do you remember 5 × 6?” If they do, then remind them (if needed) that 6 × 6 is just six more.
- Be patient with the rectangular arrays and other unfamiliar approaches. No method is perfect, but for many students and teachers their use has already proven to be more effective than what we are doing in the past.
- It should be fine to show your child the standard “line them up” ways to add and subtract (and they will see them in class too!) but realize that they may need to provide an alternate approach, especially when the standard way isn’t as efficient as some meaningful shortcut.
From Bevans and Sinha, University of Oregon Department of Mathematics, October 2014