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Learn strategies for understanding three-digit numbers, identifying values of digits, writing numbers in different forms, and enhancing addition and subtraction skills. Includes numeral representation, base-ten concepts, and word problems techniques in elementary math education.
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Math Strategies Three Digit Numbers Each digit represents amounts of hundreds, tens, and ones. 1. Bring it down: If asked to identify the value of a certain digit, students can simply bring down the number and place zero to hold the place of each following number. What is the value of the 6 in the number 769. 60 2. Knowing that each digit has a value depending on where it comes in the number. Also, knowing that each value has a certain amount of digits. 769 = 7 hundreds hundreds= 3 digit number 6 tends tens = 2 digit number 9 ones ones = 1 digit number Ways to Write a Number Standard Form = 354 Word Form = three hundred fifty-four Expanded Form= 300 + 50 + 4 = 354 Base Ten = l llll x xxx Place Value = 3 hundreds 5 tens 4 ones
Basic Facts Strategies Addition Facts; Doubles and or doubles plus 1: 5 + 6 = Add 5 + 5 = 10. Then add 1 to the 10 and the answer is 11. Make a quick ten: 6 + 9 = Take one from the six and add it to the 9. That equals 10. Then add the 5 from the 6 to the 10 and the answer is 16. Count up or Count on: 8 + 3 = Keep the 8 in your brain and count up 3. The answer is 11. Known fact: 9 + 7 = I know that 7 plus 5 equals 12. Then 12 plus 4 equals 16. The answer is 16. Subtraction Facts: Doubles and or doubles minus 1: 12 – 7 = I know that 12 minus 6 is 6. So 12 minus 7 is 1 less. The answer is 5. Subtract 10: 16 – 12 = Take 10 from 16. The answer is 6. Then subtract 2 from 6 and the answer is 4. Reversed operation and count up: 14 – 9 = Add 9 plus what number equals 14. Keep 9 in your brain and count up to 14; 10, 11, 12, 13, 14 equals five numbers. The answer is 5.
Addition Strategies Base Ten Blocks Base Ten composing (regrouping) numbers 24 + 32 = 56 l l+ l ll = l llll x xxxxxxxxx 29 + 46 =75 l l + l lll = l llllll x xxxxxxxxxxxxxx x xxxx Partial Sums Column Addition Make a quick ten, doubles, doubles plus or minus 2, or make a quick five to add the ones and the tens. Write the answer down for the ones first and then for the tens. Add together. 29 + 46 = 75 Add the ones, write it down. Add the tens, write it down. Add together for total. 29 +46 15 60 75 28 82 16 + 94 20 +200 220 10 100 10 100
Number Line Anchor the largest number on the number line and then start from the left and hop up. Check the number of hops in order to make sure you added the correct number. 25 + 47 = 72 +10 +10 +1 +1 +1 +1 +1 47 57 67 68 69 70 71 72 Hundreds Chart 25 + 47 = 72 *Student starts at 47 and moves down 2 (20) to land at 67. Then moves to right 5 spaces to get the answer 72.
Subtraction Strategies Base Ten Blocks 84 – 27 = l lllllll x xxx When using the base ten strategy. Only the larger number is drawn using base ten blocks. The smaller number is subtracted from the blocks drawn. Decompose (break apart) one of the tens and add ten ones. Then subtract. Number Line Anchor the largest number on the number line and then start from the left and hop up. Check the number of hops in order to make sure you added the correct number. 72 – 47 = 25 -40 -2 -5 70 72 25 65 Hundreds Chart 72 – 47 = 25 *Student started at 72 and moves up 4 (40) to land at 32. Then moves to left 7 spaces to get the answer 25.
Solving Word Problems • Finding the important information is crucial. Here are some strategies • recommended. • 1. make a movie in your head • 2. underline what you need to find out • 3. highlight the important information • 4. cross out information that is not needed • 5. look for key words to help know which operation to use • (more, in all, altogether, difference, less...etc.) • Part-Part- Whole Organizer -Students need to understand that numbers are • part of a whole. When solving a word problem they are given different parts. They need • to use the parts to solve the problem. 47 + 25 = ? 47 25 Mrs. Logan has 25 apples and Ms. Latimer gives her 47 more. How many apples does Mrs. Logan have in all?
Money By the end of the year, the students need to be able to solve word problems using dollars, quarters, dimes, nickels, and pennies using the cent and dollar symbol. Hairy Money Draw out circle to represent nickels, dimes, and quarters. Put a tic mark for every five in the value of the coin. Then students just count by fives to get the answer. *The tic marks look like hair. Add Groups Group amounts of money together then add all of the groups together. Example: Mona found 4 dimes, 5 nickels, and 2 quarters in the sofa. She found 4 pennies, 7 dimes, and 3 nickels in the car. How much money did Mona find altogether? 40¢ + 5¢ + 50¢ = 95¢ 4¢ + 70¢ + 15¢ = 89¢ 95¢ + 89¢= 14¢ + $1.70 = $1.84 *This is ONE strategy students learn. There are others. Partial sums is the easiest in my opinion. Students line the numbers vertically using a decimal and dollar sign. They add all of the ones, write the amount down. Then add all of the tens, write that amount down; add hundreds (dollars) if there are some. Finally they add it all together keeping the decimal and dollar sign in the correct place. Strategies: mental math, drawing hairy money, grouping, addition math strategies already mentioned.
