FOURTH GRADE ADDITION & SUBTRACTION STRATEGY GUIDE

1 Shelley Gray s ADDITION & SUBTRACTION STRATEGY GUIDE FOURTH GRADE introduction Hi there! I m Shelley Gray, and I want to challenge you to focus intensively on math facts this school year. Let s stop seeing math facts as an isolated math unit, and begin integrating them wherever possible into our math and daily solid understanding of math facts in early grades will help your students as they progress to later grades. Imagine how simple long division and multi- digit multiplication can be when the basic facts are already mastered? STRATEGY vs. memorization When we think about mastery of the math facts, we tend to think about getting a quick answer. Automaticity is a goal. This means that students can solve a fact within 1-3 seconds, and just know the answer. But there is more to it!We want to teach our students to be flexible thinkers when it comes to solving an equation.

2 This means that they are able to manipulate the numbers in different ways in order to solve a problem. The steps that one student takes to solve a problem might be very different than the steps that another student takes. We want to celebrate this flexible thinking!Math fact fluency should not be based on the ability to perform a memorized series of steps. It is so much more than goals Throughout your math fact instruction and practice this year, try to keep three main words in mind when it comes to how your students are solving a problem or equation: EFFECTIVE, EFFICIENT, FLEXIBLE. Is the STRATEGY effective and efficient (is it quick and works well)? Are they able to think flexibly with the numbers? Shelley to use this GUIDE This GUIDE is intended as a reference GUIDE for the various mental math strategies that are best-suited to your particular GRADE can be really confusing to teach math strategies.

3 How do you integrate them? When do you move on to the next one? How do you differentiate to the different ability levels?My hope is that this GUIDE gives you a starting point for reinforcing the strategies. Begin with the first STRATEGY , allow your students to master it, and then move along to the next you are not in our 30-Day Math Fact Challenge private Facebook group yet, be sure to join so that you collaborate with other teachers who have the same goals as you. Join here: Shelley You do not need to purchase any resources to reinforce these strategies. You simply need a commitment to teaching and reinforcing them throughout the , if you would like a complete system to help you do this, here is a link to The FOURTH GRADE ADDITION Station and The FOURTH GRADE SUBTRACTION Station, which will reinforce all of the strategies that are outlined in this GUIDE .

4 The entire ADDITION and SUBTRACTION Station programs are self-paced so that students will move through the strategies as they feel Station: SUBTRACTION Station: What s included? QUICK REFERENCE CARDSThe Quick Reference Cards can be laminated and put on a ring for quick and easy reference to the strategies that are best suited for this GRADE can also be used for oral assessments. I highly recommend oral assessments to assess math STRATEGY knowledge. When you SEE a student solve an equation, you get a far different perspective than you do when you simply mark a written solution. Oral assessments enable you to see which facts/strategies a student struggles with, which ones are quicker than the rest, and which strategies are used to solve a assessment is the assessment method that is used in all of my math stations. Although this might seem like a huge task, it only takes about 1-2 minutes, and many teachers report that it is their favorite part of using the you would like to try oral assessments, you can use the Quick Reference Cards from the previous few pages as a GUIDE .

5 Look for the following: Is he using an effective STRATEGY to solve the equation? Is his STRATEGY efficient? (meaning that he can solve the equation in 1-3 seconds) Can you see flexibility in his thinking? (is he able to manipulate the numbers in a flexible way to make the STRATEGY work for him?)In this STRATEGY GUIDE you will find Quick Reference Cards and a timed test for TESTST imed tests do not work for every student. However, they can be useful to assess fact ve included a timed test sheet following the Quick Reference you choose to use them in your classroom, here are some ideas for use: Focus on self-improvement and self-growth over time rather than competition with classmates. Do not force a student to perform a timed test if it causes stress to him/her. Have students perform the assessment once every 2 weeks to assess self-improvement.

6 Only expect to see growth if fact practice is a regular part of the classroom PAGES 7-11 Plus 0 Example: 16+0=16 Any number plus 0 equals that number. 110+0=110250+0=2502392+0=2392655+0=65530 +0=301255+0=1255409+0=40964+0=642003+0=2 003388+0=388 Sample Equations: Plus 1 Example: If 6+1=7, then 60+10=70 and 600+100=700 Any number plus 1 is one more than that number.*Extend to 10 s, 100 s, and 1000 s. Sample Equations: Plus 2 Sample Equations: ADDITION STRATEGIES QUICK REFERENCE CARDS FOR FOURTH GRADE +1=2221097+1=1098564+1=565477+1=4782909+ 1=291030+10=40400+100=5007000+1000=80005 0+10=602000+1000=3000 Example: If 6+2=8, then 60+20=80 and 600+200=800 Any number plus 2 is two more than that number.*Extend to 10 s, 100 s, and 1000 s. 256+2=2581981+2=1983457+2=4592036+2=2038 562+2=56440+20=60500+200=70080+20=100600 0+2000=8000300+200=500 DOUBLES Example: If 3+3=6, then 30+30=60 and 300+300=600 Have your students try to memorize the doubles facts.

7 Then practice extensions to the tens, hundreds, and thousands. Sample Equations: DOUBLES PLUS ONE Example: If 3+4=7, then 30+40=70 and 300+400= double plus one more. Also, extend to tens and hundreds. 5+6=119+10=191+2=33+4=78+9=172+3=57+8=15 6+7=134+5=910+11=21 Sample Equations: DOUBLES Plus 2 Example: If 3+5=8, then 30+50=80 and 300+500= double of the number plus 2 more. Also, extend to tens and hundreds. 200+400=6003+5=830+50=807+9=166+8=141+3= 48+10=182+4=65+7=1250+70=12010+12=22100+ 300=400 Sample Equations: PLUS 3 Sample Equations: 1+1=22+2=430+30=60300+300=60040+40=804+4 =85+5=106+6=127+7=1470+70=1408+8=169+9=1 810+10=2011+11=2212+12=2411+12=2310+20=3 060+70=130300+400=700200+300=500 Example: If 6+3=9, then 60+30=90 and 600+300=900 Any number plus 3 is three more than that number.*Extend to 10 s, 100 s, and 1000 s. 822+3=825467+3=4701075+3=1078245+3=24810 01+3=10043275+3=327840+30=70500+300=8006 000+3000=900070+30=100400+300=700200+300 =5003000+3000=60004000+4000=80003000+400 0=70004000+5000=90003000+5000=80002000+4 000=6000 Adding 10 s and 100 s Example: To solve 234+20, just add two groups of 10 to the tens place to make groups of 10 or 100 to the tens and hundreds place.

8 Sample Equations: PLUS 7, 8, and 9 (for numbers ending in 7, 8, or 9) Example: For 226+8, think, I could take 2 from the 226 and add it to the 8 to make 10, and then add the leftover 224 to make 234. Take from one number and give to the other to make a number that is easier to work with. 829+8=837427+6=433568+7=57548+8=566819+2 =6821 Sample Equations: Adding 1000 s Sample Equations: Making 10, 100, and Making 1000 Example: What can you add to 6 to make 10? What can you add to 60 to make 100? Know the ADDITION facts that make 10. Use these facts to make 100 and 1000. 8+___=104+___=106+___=101+___=109+___=10 Sample Equations: 3+___=107+___=1010+___=102+___=105+___=1 073+10=83449+30=479127+20=147780+200=980 6145+200=63453000+700=37005314+40=535476 00+200=7800275+400=675569+10=57977+9=863 9+5=445018+5=5023108+4=112509+4=513 Example: For 324+1000, add one group of 1000 to make groups of 1000 to the 1000 s place.

9 1002+1000=2002389+2000=2389354+1000=1354 2441+3000=54416873+2000=88731346+1000=23 46231+2000=2231719+1000=1719367+1000=136 72445+3000=544530+___=10020+___=100400+_ __=100050+___=100700+___=1000 Left-to-right ADDITION Example: To solve 23+12, first add 20+10 to make 30, then 3+2 to make 5. Then add 30+5 to make the thousands first, then the hundreds, then the tens, then the ones. Sample Equations: Using friendly numbers Example: For 418+6, start with 418 and add 2 to get to 420, then add the remaining 4 to make 424. Bridge to a friendly number, and then add the remainder. (Number lines are useful for this STRATEGY .) Sample Equations: 466+7=47379+4=83615+7=62267+5=721217+5=1 222116+7=1234857+9=48661675+6=16812108+5 =2113345+6=35112+45=57115+212=32780+19=9 961+18=7931+32=637202+2313=951523+24=477 611+2310=9921180+301=48154+11=6534+13=47 256+122=37813+14=2743+24=6775+13=88 Break up the second number Example: To solve 25+34, first add 25+30 to make 55, then 55+4 to make 9.

10 Break the second number into its expanded fo r m a n d t h e n a d d i n p a r t s . Sample Equations: 18+11=29120+25=14543+32=7556+42=98167+12 1=2881423+350=177393+24=117202+374=57635 +57=9225+33=58compensation Example: To solve 34+49, first solve 34+50 to make 84. Since we added one to the equation, we take 1 away from the answer to make one of the addends to make it more manageable. Then adjust the sum to make up for the original change. Sample Equations: 32+38=7041+72=11364+47=111302+39=341250+ 252=5021213+211=14242500+313=2813510+213 =723240+141=38122+62=84 How many equations can you solve in 1 minute? ADDITION FACTS TO 10,000 176+3=_____ 50+60=_____ 500+300=_____ 77+9=_____ 200+100=_____ 11+11=_____ 4000+2000=_____ 39+5=_____ 7+7=_____ 1456+400=_____ 11+12=_____ 145+2=_____ 600+400=_____ 1242+0=_____ 30+50=_____ 900+900=_____ 3289+400=_____ 600+800=_____ 68+7=_____ 4000+4000=_____ DATE: _____ Total: _____ My goal for next time.