Math · Unit 1 · Weeks 1–6
Place Value, Adding & Subtracting, Multiplication Begins
The big idea
Your child starts the year by reading, comparing and rounding three-digit numbers, then uses place value to add and subtract within 1,000, including regrouping across zeros. In Week 4 multiplication begins with equal groups and arrays, and the unit ends with the ×2, ×5 and ×10 facts.
Standards in plain words
- 3.NBT.A.1 Uses place value to round whole numbers to the nearest 10 or 100.
- 3.NBT.A.2 Adds and subtracts within 1,000 quickly and accurately, using strategies and written methods based on place value.
- 3.OA.A.1 Understands a product like 5 × 7 as the total number of objects in 5 equal groups of 7.
- 3.OA.A.3 Uses multiplication and division within 100 to solve word problems about equal groups, arrays and measurements, with drawings and equations that use a symbol for the unknown number.
- 3.OA.C.7 Multiplies and divides within 100 quickly and accurately using strategies, and by the end of the year knows from memory all products of two one-digit numbers.
- 3.OA.D.8 Solves two-step word problems with all four operations, writes equations with a letter for the unknown, and checks that answers make sense with mental math, estimation and rounding.
- 3.OA.D.9 Finds patterns in the addition and multiplication tables and explains them with properties of operations, for example why 4 times any number is even.
What mastery looks like
- Says what each digit in a number like 507 is worth and writes it in expanded form (500 + 7).
- Rounds to the nearest 10 and 100 by naming the two tens or hundreds a number sits between, as in 297 rounding to 300.
- Adds and subtracts three-digit numbers with regrouping, including problems like 500 − 137, and checks with an estimate.
- Draws equal groups or an array for a multiplication sentence and names the factors and the product.
- Answers ×2, ×5 and ×10 facts quickly using doubles, fives patterns and place value.
Materials
- Base-ten blocks, or bundles of 10 straws and single straws
- Place-value chart with hundreds, tens and ones columns
- Graph paper (one digit per square)
- Counters such as dried beans
- Number lines marked by tens and hundreds
- Index cards for <, > and = and for fact cards
- Timer
Watch across the unit
Watch for: Naming a digit instead of its value, such as saying the 7 in 374 is worth 7.
Try: Ask 'How many ones is that 7 really worth?' and show 7 ten rods to see 70.
Watch for: Taking the smaller digit from the larger one in every column, so 500 − 137 becomes 437.
Try: Rewrite 500 as 4 hundreds, 9 tens and 10 ones above the problem before subtracting, and check by adding back.
Watch for: Mixing up the number of groups and the number in each group (writing 4 × 3 for 4 + 4 + 4).
Try: Draw the circles for the groups first, fill each with the same number of dots, then count the addends aloud: 'three 4s is 3 × 4.'
Pacing
Short week: Keep Monday's lesson, where the week's idea is built with blocks or counters, and the Friday check. Combine the two middle practice days into one, and keep the 5-minute fact fluency warm-up every day you teach.
Flex week: Week 5 is the flex week. Use the Friday checks from Weeks 1 to 4 to choose: catch up on regrouping errors, practice rounding and arrays, or go deeper with the place-value number riddles and the array garden design. End with the Week 5 review so you know what to watch in Week 6.
Week by week
| Week | Topic | Check |
|---|---|---|
| Week 1 | Place value to 1,000, comparing & rounding | Read, write, compare and round 3-digit numbers |
| Week 2 | Adding within 1,000 with regrouping | Add 3-digit numbers and solve addition word problems |
| Week 3 | Subtracting within 1,000, including across zeros | Subtract with regrouping and solve word problems |
| Week 4 | Multiplication as equal groups & arrays | Write multiplication sentences for groups and arrays |
| Week 5 | Flex week: catch up, deepen or enrich | Choice practice on Weeks 1–4 |
| Week 6 | Multiplication facts: ×2, ×5, ×10 | Unit 1 test |