3rd Grade Math Skills & Strategies

Problem of the Day Strategies Find (Identify the question) Know (Gather Information) Strategies: Draw a picture Make an organized list Make a table Make a graph Act it out Look for a pattern Try, check, revise Write an equation Use reasoning  ALWAYS!!  Work backwards Solve a simpler problem 4. Show the problem (work it out) 5. Solution (the answer to the problem) 6. Answer (in a complete sentence) 7. Check for reasonableness, evaluate (do the opposite: add/subtract, multiply/divide, etc.)

Word Problem Strategies Read the word problem. Find and underline the question. Box out key words & vocabulary words. Circle numbers you need, underline labels, mark out any distractors. Choose your strategy. Solve the problem (show your work!) Prove your answer. If labels are the same = ADD or SUBTRACT! If labels are different = MULTIPLY or DIVIDE! Watch for 2-step problems! Watch for EXTRA or MISSING information! Check answer for reasonableness!

Place Value Standard Number Form: 43,621 Word Form: Forty-three thousand, six hundred twenty-one Expanded Notation: 40,000 + 3,000 + 600 + 20 + 1 Pizza Place Value: 43,621 (line the numbers up correctly and it will 40,000 look like a slice of pizza!) 3,000 600 20 1 HTO Chart: 100TH 10TH TH H T O 4 3 6 2 1 Digit: Number Value: The worth of something.

Patterns ____ ____ ^ Repeating Pattern: Growing Pattern: A B C A ____ Repeating Pattern: Growing Pattern: T-Chart: ---------------------------------- # of months Number Pattern: 2, 4, 6, 8, __, 12, 14…. Teepee: ^ Rule: example=(+2) Stem ____ 1 Month 2 Months 3 Months 4 Months 5 Months? # of leaves 1 2 3 4 5 1 2 3 4 ? +2 ^

Money . “Hairy Money” Currency: the money that is used in a country. 1 cent 5 cents 10 cents 25 cents 50 cents . Currency: the money that is used in a country.

Telling Time Analog: physical measurement Digital: electronic signal Quarter Before: 15 minutes before the hour Quarter After: 15 minutes after the hour Look at the hour hand (shortest) and say the number. If it is between the numbers you say the lowest number or the number before. 2. Look at the minute hand (longest), count by 5’s and say the number. If it is on 60, say “o’clock”.

Addition with Regrouping 475 + 136 _____ 611 The answer to an addition problem is called the SUM. Put big number on top to help remember for subtraction. Make sure the numbers are lined up (ones with ones, tens with tens…) Look at the ones place; if the two numbers equal ten or more you will regroup. Bring the ones place down to the ones place and carry the ten to the tens place. Look at the tens place and add the regrouped number. Add all the numbers in the tens place. If the numbers equal ten or more you will regroup. Repeat steps 3 and 5. Sum, How many are there, Added/Plus, Total, In all, Altogether, And…

Subtraction with Regrouping “More on top, don’t stop! More on the floor, go next door!” “Numbers the same, zeros the game!” The answer to a subtraction problem is called the DIFFERENCE. How many more/less, How many are left, Spent, Difference… Place the bigger number on top. Make sure numbers are lined up (ones with ones, tens with tens, etc.) Start at the ones place and look at the numbers to see if you can subtract without regrouping. If the top number is bigger, you can just subtract. If the top number is smaller (less than) the bottom number, you have to regroup. Take one ten from the tens place and cross it out (it becomes one less) (example: 3 turns into 2). Add the ten to the ones place. Subtract the ones. Look at the tens & repeat steps 3-8. 7 3 2 9 ------ 4 4

Don’t forget your teepees! (^) Number Lines Look for the RULE! Try numbers until you find the rule. 31, 37, ___, 49 (Rule +6) (Rule -5) 25 ___ 15 10 Don’t forget your teepees! (^)

The corners are called VERTICES. 2D & 3D Shapes Face Edge Sides Vertices The corners are called VERTICES. Rectangular Prism

Perimeter Outside – Add ALL of the sides! + 90 ------- 90 Perimeter: the length of the border.

Area Inside – Count what you are looking for. Area: the amount of surface within a certain space. Inside – Count what you are looking for. * Watch for shaded or NOT shaded!

Multiplication Ways to solve: Gets bigger! Ways to solve: Loops & Groups 2. Array 3. Repeated addition 4. T-Chart 5. Algorithm (aka “up & over”) (you have to have your facts memorized to use this method!) The answer to a multiplication problem is called a PRODUCT. I I I I I I I I I I I I = 12 4 . . . . 3 . . . . 4 + 4 + 4 = 12 3 X 4 3 4 4 X 3 X 4 X 3 ----- ----- Product, Times, Twice,…

Greater & Less Than Greater Than 36 > 29 Less Than 15 < 57

Fractions Fraction-an equal part of a whole number. Numerator-tells us how many parts; “UP!” Denominator-tells us all the equal parts; “DOWN!” Equivalent-the same of equal. 3 1 --- are shaded --- is not shaded 4 4

When you see ESTIMATE or ABOUT, “round FIRST, then solve”! Rounding – Part 1 “Round to the nearest…” “About how many,,,” “About” Estimate when you don’t need an exact answer. Estimate to check your work. When you see ESTIMATE or ABOUT, “round FIRST, then solve”!

Rounding – Part 2 90 93 40 38 ------ ------ 50 Remember: When it’s in the middle (5), you round up! 25=30 Find the digit, Look next door. Five or higher, Add one more! Four or less, Let it rest! Rounds to 90 40 ------ 50 93 38 ------ 0,1,2,3,4 = go to lowest 10 5,6,7,8,9 = go up to highest 10 Rounds to

Temperature F C Boiling 212 100 Freezing 32 0

Fact Families Addition/Subtraction fact families are found by: Starting with a simple fact. ( 2 + 5 = 7) Changing the numbers around. (5 + 2 = 7) Writing the Inverse operations for both. (7 - 2 = 5 & 7 - 5 = 2) Multiplication/Division fact families are found by: Starting with a simple multiplication fact. ( 3 x 9 = 27) Changing the multiplicands around. (9 x 3 = 27) Writing the Inverse operations for both. (27 / 3 = 9 & 27 / 9 = 3)

Division 12 / 4 = 3 I I I I I I I I I I I I I I I I Division Monster Gets smaller! Look for these words to divide: Separate, give, each, equal… 12 / 4 = 3 I I I I Array The answer to a division problem is called a QUOTIENT. Loops & Groups I I I I I I I I I I I I I I I I Division Monster 12 Separate, Equal, Half, Each (in the question)…

Measurement 12 inches = 1 foot = “your ruler” or “piece of paper” 3 feet = 36 inches = 1 yard = “yard stick” 1 meter = “light on ceiling” 1 mile = 5,280 feet = “school to Wal-Mart” 1 inch = “end of finger” 1 cm = 0.01 meter = “width of pinky”

Congruence Congruent-same size AND shape.

Symmetry Symmetry-one object that when an imaginary line is drawn through is the same at both ends. Line of Symmetry-a line that divides a figure/shape into two mirror images. Line of Symmetry

Graphs

Paired Numbers To make two batches of cookies how many eggs do you need? For three batches? For four batches? How did you find the number of eggs needed to make four batches of cookies?

Probability “More likely than”, “Less likely than”, “Equally likely as”…

Range 12-24 3 6 X X 4 The range (answer) Lowest number Highest number *With range, you will either multiply or divide. 4 The number that only has 1 label.