Regrouping Rescue Worksheet- Regrouping Rescue 3-Digit Subtraction with Place-Value Base-Ten Visuals Name: Date: Strategy More on the floor? Go next door and take 10 more! 1 Hundred = 10 Tens 1 Ten = 10 Ones 1 Find the difference: 542 − 128 Regroup 1 Ten into 10 Ones Calculation Grid H T O 5 4 2 − 1 2 8 Base-Ten Model for 542 Trade 1 ten rod for 10 ones units! Hundreds (5) Tens (4) TRADE Ones (2 + 10 = 12) Cross out 8 ones to subtract Cross out: 1 hundred, 2 tens, 8 ones. What remains? 2 Find the difference: 615 − 243 Regroup 1 Hundred into 10 Tens Calculation Grid H T O 6 1 5 − 2 4 3 Base-Ten Model for 615 Trade 1 hundred flat for 10 tens rods! Hundreds (6) TRADE 5 flats left after trade Tens (1 + 10 = 11) Cross out 4 tens to subtract Ones (5) Cross out 3 ones to subtract Cross out: 2 hundreds, 4 tens, 3 ones. What remains? PRACTICE Double Regrouping & Zero Zappers Regrouping Rescue • Page 2 of 3 3 Double Regroup: 734 − 358 Both Ones and Tens Need Regrouping! H T O 7 3 4 − 3 5 8 Draw or Model Base-Ten Blocks Draw: □ = 100, | = 10, • = 1 Hundreds Tens Ones Check Step: Did you trade 1 ten for 10 ones? Did you trade 1 hundred for 10 tens? 4 Zero in the Tens: 504 − 176 Zero Trap: Go to Hundreds First! H T O 5 0 4 − 1 7 6 Zero Regrouping Pathway A Cannot borrow from 0 tens! Take 1 hundred from 5 hundreds (leaves 4). Now you have 10 tens! B Now take 1 ten from 10 tens (leaves 9 tens). Give 10 ones to 4 ones to make 14 ones! 5 becomes 4 ➔ 0 becomes 9 ➔ 4 becomes 14 5 Real-World Mystery: Library Book Count Story Problem The Pine Ridge Library started the summer with 425 mystery books on display. By the end of July, young readers had checked out 187 books. How many mystery books remain on the library display? Part-Part-Whole Bar Model 187 checked out ? books left Total Books: 425 4 2 5 − 1 8 7 Answer: There are mystery books left on the library shelves. Solo Practice Independent Challenge (Without Assistance) Regrouping Rescue • Page 3 of 3 Directions: You are on your own! Use your regrouping skills to subtract. Show all your trades in the calculation grid and use the open space to show your work or check your answer. 6 Calculate: 843 − 467 Independent Calculation Grid H T O 8 4 3 − 4 6 7 My Work & Addition Check Show your calculations or check: Difference + Subtrahend = Minuend Did you check your work? Yes, checked! 7 Calculate: 902 − 538 Independent (Zero in Tens) Calculation Grid H T O 9 0 2 − 5 3 8 My Work & Addition Check Show your calculations or check: Difference + Subtrahend = Minuend Did you check your work? Yes, checked! Self-Check How confident do you feel solving 3-digit subtraction without assistance? Still Practicing Getting Good Regrouping Master!
Regrouping Rescue Answer Key✓ Regrouping Rescue Answer Key Teacher Reference & Worked Solutions with Regrouping Annotations Page 1 of 3 Teacher Tip Check digit cancellation: students must cross out before subtracting! #1 Difference: 414 #2 Difference: 372 1 Worked Solution: 542 − 128 Answer = 414 Calculation Grid — 3 12 H T O 5 4 2 − 1 2 8 4 1 4 Instructional Walkthrough STEP 1 Ones: 2 is less than 8. Regroup 1 ten from 4 tens. 4 becomes 3 tens and 2 becomes 12 ones. 12 − 8 = 4 ones. STEP 2 Tens: Subtract remaining tens: 3 − 2 = 1 ten. STEP 3 Hundreds: 5 − 1 = 4 hundreds. Check with Addition: 414 + 128 = 542 ✓ 2 Worked Solution: 615 − 243 Answer = 372 Calculation Grid 5 11 — H T O 6 1 5 − 2 4 3 3 7 2 Instructional Walkthrough STEP 1 Ones: 5 > 3. Direct subtraction: 5 − 3 = 2 ones. STEP 2 Tens: 1 < 4. Borrow 1 hundred from 6 hundreds. 6 becomes 5 hundreds, 1 becomes 11 tens. 11 − 4 = 7 tens. STEP 3 Hundreds: 5 − 2 = 3 hundreds. Check with Addition: 372 + 243 = 615 ✓ SOLUTIONS Double Regrouping & Real-World Problem Answer Key • Page 2 of 3 3 734 − 358 (Double Regrouping) Answer = 376 6 12 14 H T O 7 3 4 − 3 5 8 3 7 6 Regrouping Chain Reaction 1. Ones: Borrow 1 ten from 3 tens. 3 becomes 2 tens; 4 becomes 14 ones. ➔ 14 − 8 = 6 2. Tens: Now 2 tens minus 5 tens cannot be done. Borrow 1 hundred from 7 hundreds. 7 becomes ; 2 becomes . ➔
Thinkers and Builders Article🔬 Thinkers and Builders What Do Scientists and Engineers Do? Name: Date: 📖 Reading Tip: Read the article carefully. Look closely at the bold words! Grade 2–3 Science 1 What Is a Scientist? A scientist is a person who wants to understand how the natural world works. Scientists are very curious. They look closely at things and ask big questions like: Why is the sky blue? How do plants grow? What makes volcanoes erupt? To find answers, scientists observe things using their five senses. They also do experiments. An experiment is a fair test to see what happens. Scientists write down what they learn as data so they can share facts with the world. 2 What Is an Engineer? An engineer is a person who uses math and science to solve problems. While scientists ask "Why does this happen?", engineers ask "How can I fix this?" Engineers create a design, which is a plan for a new invention. Then they build a prototype, which is a test model. If their model breaks, they do not give up! They test it again, improve it, and build things that help people every day, like bridges, airplanes, wheelchairs, and clean water filters. 3 Working Together as a Team Scientists and engineers work together through teamwork. A scientist might discover how electricity flows through wires. Then, an engineer uses that discovery to build a smartphone or a flashlight! Together, they make our lives safer, healthier, and brighter. 🔍 Scientist Summary • Goal: Discover new knowledge • Action: Asks questions and tests ideas • Key Tool: Experiments and observations ⚙️ Engineer Summary • Goal: Solve real-world problems • Action: Designs and builds inventions • Key Tool: Prototypes and testing CHECKUP Comprehension Questions Thinkers and Builders • Page 2 of 2 1. What is the main goal of a scientist? A To sell tools in a hardware store
Thinkers and Builders Answer Key✓ Thinkers and Builders Answer Key Teacher Comprehension Key & Text Evidence Guide Quick Check Quick Key: 1: B 2: A 3: B 4: A 5: C 1. What is the main goal of a scientist? Correct: B Text Evidence (Section 1): "A scientist is a person who wants to understand how the natural world works." Scientists ask big questions and observe nature to discover new facts. 2. According to the article, what is an experiment? Correct: A Text Evidence (Section 1): "An experiment is a fair test to see what happens." Scientists conduct fair tests to collect data and verify their predictions. 3. What question is an engineer most likely to ask? Correct: B Text Evidence (Section 2): "While scientists ask 'Why does this happen?', engineers ask 'How can I fix this?'" Engineers are problem-solvers who focus on creating practical solutions. 4. What is a prototype? Correct: A Text Evidence (Section 2): "Then they build a prototype, which is a test model." Engineers build prototypes to test whether their design works before manufacturing the final product. 5. How do scientists and engineers work together? Correct: C Text Evidence (Section 3): "A scientist might discover how electricity flows through wires. Then, an engineer uses that discovery to build a smartphone or a flashlight!" Scientific discoveries provide the knowledge engineers use to build tools. Class Discussion Prompts Prompt A: "Think of an object in our classroom (like scissors or a pencil sharpener). Did a scientist, an engineer, or both help create it?" Prompt B: "Why is it okay if an engineer's first prototype fails or breaks during testing?"
