Third Grade Mathematics
First Nine Weeks
These objectives listed below will be covered in the 1st Nine Weeks Unit of study.
Addition and Subtraction
Add and subtract within 1000 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.
Use place value understanding to round whole numbers to the nearest 10 or 100.
Multiply and divide to solve problems
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.
(This will continue all school year)
Understand division as an unknown-factor problem.
For example, find 32 ÷ 8 by finding the number that makes 32 when multiplied by 8.
Concepts of area
Relate area to the operations of multiplication and addition, show that the area is the same as would be found by multiplying the side lengths.
Reason with shapes and understand their attributes.
Here are some suggestions as to what you can do at home to help your child
Many of the techniques for addition and subtraction are easily done mentally without recording. It is not at all unreasonable for students to be able to add and subtract two-digit numbers mentally by third grade. Recording of strategies helps communicate ideas and helps assist short term memory of the steps.
Your child is learning to add and subtract numbers mentally. Your child can do mental math to find sums such as 200+400=600 or to estimate sums and differences. For example, 32+69=? As 30+70=100 so 32+69 is about 100.
As you go through your daily activities encourage your child to add and subtract mentally. (Suggestion: when on a trip estimate how far a round trip would be if one way is 48 miles).
Make a set of digit cards by writing one digit on each card. Make a card for
each digit 0 – 9. Place the cards face down on the table. Player 1 turns over three
Player 1 arranges the 3 digits to make the least possible 3-digit number and
records the number
Player 2 then rearranges the cards to make the greatest possible number and
Repeat the game several times using 3 digit numbers. Then play using 4 cards, 5
cards, or 6 cards to make larger numbers.
Add Them Fast
Make number cards: 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000
Mix the number cards and place them face down on a table
Each player turns over 2 cards and uses mental math to find the sum of the two
numbers shown. The player with the greater number keeps all 4 turned cards.
Help your child "see" multiplication and division by using real items like raisins, coins, or paper squares, or by letting him draw items to represent the equations.
Help your child understand shapes in different categories. For example, these shapes are examples of quadrilaterals, which are flat shapes with four straight sides.
*Rhombus - four-sided shape where all sides have equal length. Also, opposite sides are parallel and opposite angles are equal. A square would be a rhombus but a rectangle with unequal sides would not.
*Rectangle - rectangle is a four-sided polygon (a flat shape with straight sides) where every angle is a right angle (90°). A rectangle might be a square, but often is not a square.
*Square - A 4-sided polygon (a flat shape with straight sides) where all sides have equal length and every angle is a right angle (90°). A square is always a rectangle.
*Parallelogram - Opposite sides are parallel and equal in length, and opposite angles are equal (angles "a" are the same, and angles "b" are the same)
*Trapezoid - trapezoid is a quadrilateral with one pair of opposite sides parallel