Adding and subtracting within 20
Students get quick and confident with small addition and subtraction facts. They learn to solve these in their head and start to know the answers by heart.
This is the year numbers grow past 100 and students start thinking in hundreds, tens, and ones. They add and subtract within 100 quickly in their heads, count past 1,000, and work with money up to a dollar. They also learn to measure with rulers and read a clock to the nearest five minutes. By spring, students can solve a two-step word problem and split a rectangle into halves, thirds, or fourths.
Students get quick and confident with small addition and subtraction facts. They learn to solve these in their head and start to know the answers by heart.
Students learn that a three-digit number is made of hundreds, tens, and ones. They read, write, and compare numbers up to 1000 and skip-count by 5s, 10s, and 100s.
Students add and subtract numbers up to 100 fluently, then stretch to 1000 using drawings and place value. They also solve word problems with one or two steps.
Students measure objects with rulers in inches and centimeters, tell time on a clock to the nearest five minutes, and count coins up to a dollar.
Students name shapes, split circles and rectangles into halves, thirds, and fourths, and read simple picture and bar graphs. They also build arrays as a first look at multiplication.
| Standard | Definition | Code |
|---|---|---|
| Polygons vs. non-polygons | Students sort flat shapes into two groups: polygons (closed figures made of straight sides, like triangles and rectangles) and non-polygons (circles or any shape with curved or open edges). | NY-2.G.1 |
| Divide a rectangle into equal squares | Students cut a rectangle into equal squares arranged in rows and columns, then count all the squares to find the total. It's an early look at how multiplication and area work. | NY-2.G.2 |
| Splitting shapes into equal parts | Cutting a circle or rectangle into equal pieces, students name each piece as a half, a third, or a fourth. Two halves make a whole, and equal pieces don't have to look the same to be the same size. | NY-2.G.3 |
| Standard | Definition | Code |
|---|---|---|
| Measuring length with rulers and tape measures | Students pick the right measuring tool, such as a ruler or tape measure, and use it to find how long an object is to the nearest whole inch or centimeter. | NY-2.MD.1 |
| Measuring with different units | Students measure the same object twice using two different units, like paper clips and then inches. They explain why the numbers differ and how a smaller unit always produces a bigger count. | NY-2.MD.2 |
| Estimating lengths in inches, feet, and centimeters | Students look at an object and make a reasonable guess about its length before measuring. They practice thinking in inches, feet, centimeters, and meters. | NY-2.MD.3 |
| Comparing lengths with a ruler | Students measure two objects and find the difference in length, saying something like "the pencil is 3 inches longer than the eraser." They practice subtracting measurements to describe how much longer one thing is. | NY-2.MD.4 |
| Word problems with lengths and measurements | Students solve story problems where two lengths are added or subtracted, like finding the total length of two ropes or how much shorter one shelf is than another. All measurements use the same unit, such as inches or centimeters. | NY-2.MD.5 |
| Number lines for adding and subtracting | Students place whole numbers on a number line and use it to add and subtract. Each jump between marks is the same size, and the answer lands somewhere between 0 and 100. | NY-2.MD.6 |
| Telling time to the nearest five minutes | Students read analog and digital clocks to the nearest five minutes and write the time using a.m. or p.m. They also learn phrases like quarter past, half past, and quarter to. | NY-2.MD.7 |
| Measure objects and plot the lengths | Students measure several objects with a ruler and record each length as a whole number. Then they plot the results on a simple number-line graph to see how the measurements compare. | NY-2.MD.9 |
| Picture graphs and bar graphs | Students collect information in up to four categories, then draw a picture graph or bar graph to show it. They use that graph to answer questions like how many more or how many in all. | NY-2.MD.10 |
| Counting mixed coins up to a dollar | Students count a mixed handful of pennies, nickels, dimes, and quarters to find the total value. The total stays at one dollar or less. | NY-2.MD.8a |
| Counting coins up to one dollar | Students add up coins (quarters, dimes, nickels, and pennies) to solve everyday money problems under a dollar, writing the total with the cent symbol. | NY-2.MD.8b |
| Standard | Definition | Code |
|---|---|---|
| Hundreds, tens, and ones in 3-digit numbers | Students learn that a three-digit number like 347 is built from hundreds, tens, and ones stacked together. Ten groups of ten make a hundred, and numbers like 200 or 800 are simply two or eight of those hundreds with nothing left over. | NY-2.NBT.1 |
| Counting and skip-counting to 1,000 | Starting from any number, students count forward to 1000 and practice jumping by 5s, 10s, or 100s, the way a clock counts by 5s or a ruler jumps by 10s. | NY-2.NBT.2 |
| Reading and writing numbers to 1000 | Students read and write numbers up to 1,000 three ways: as a numeral (347), as words (three hundred forty-seven), and broken into parts (300 + 40 + 7). | NY-2.NBT.3 |
| Comparing three-digit numbers with >, =, and < | Students look at two three-digit numbers and decide which is bigger, smaller, or equal by comparing the hundreds, then tens, then ones. They write the answer using the symbols >, <, or =. | NY-2.NBT.4 |
| Adding and subtracting within 100 | Students add and subtract any two numbers up to 100 quickly and accurately. They use what they know about tens and ones, not just memorized steps, to find the answer. | NY-2.NBT.5 |
| Adding up to four two-digit numbers | Students practice adding as many as four two-digit numbers at once by breaking numbers into tens and ones to make the math easier to manage. | NY-2.NBT.6 |
| Mental math: add and subtract 10s and 100s | Students add or subtract 10 or 100 from a three-digit number without writing anything down. They spot the pattern: only one digit in the number changes. | NY-2.NBT.8 |
| Why addition and subtraction strategies work | Students explain *why* a math strategy works, not just what the answer is. They use what they know about tens and ones to show why adding or subtracting a certain way makes sense. | NY-2.NBT.9 |
| Adding and subtracting numbers up to 1000 | Students add and subtract numbers up to 1000 by drawing pictures or using blocks, then explain how their method connects to what they wrote on paper. The work shows they understand hundreds, tens, and ones. | NY-2.NBT.7a |
| Adding and subtracting three-digit numbers | Adding or subtracting three-digit numbers means lining up hundreds, tens, and ones and working column by column. Sometimes a column doesn't have enough to subtract or has too many to fit, so students regroup between columns. | NY-2.NBT.7b |
| Standard | Definition | Code |
|---|---|---|
| Rows and columns: adding up arrays | Students count objects arranged in a grid of rows and columns, then write an addition sentence to show the total. For example, 3 rows of 4 dots becomes 4 + 4 + 4 = 12. | NY-2.OA.4 |
| Addition and subtraction word problems within 100 | Students read a short story problem and figure out a missing number by adding or subtracting, with any part of the problem left unknown: the starting amount, the change, or the final total. | NY-2.OA.1a |
| Two-step word problems within 100 | Two-step word problems ask students to solve two separate math questions in a row before reaching the final answer. Students add or subtract numbers up to 100 and work through situations like combining groups, removing items, or figuring out how many more one group has than another. | NY-2.OA.1b |
| Adding and subtracting within 20 from memory | Students add and subtract any two numbers up to 20 in their heads, without counting on fingers. They learn a handful of mental shortcuts to get there faster, like building to ten or using a known fact to figure out a harder one. | NY-2.OA.2a |
| Addition facts up to 20 from memory | Students have memorized every addition fact up to 9 + 9 without counting on their fingers or pausing to figure it out. Fast recall here frees up mental space for harder math. | NY-2.OA.2b |
| Odd and even numbers up to 20 | Students look at a group of up to 20 objects and decide if the count is odd or even. They check by pairing objects up and seeing if any are left over. | NY-2.OA.3a |
| Even numbers as two equal addends | Students write a number sentence showing that an even number is the sum of two matching numbers, like 12 = 6 + 6. This shows why even numbers can always be split into two equal groups. | NY-2.OA.3b |
All New York public school students take this math test in the spring of grade 3. It covers the Next Generation grade 3 standards, with multiple-choice and constructed-response questions.
The alternate state test for students with the most significant cognitive disabilities. NYSAA replaces the Grade 3-8 tests and Regents exams in ELA, math, and science for the small group of students whose IEP teams qualify them.
Students should add and subtract within 100 quickly, know sums within 20 from memory, and work with numbers up to 1000 by hundreds, tens, and ones. They should also measure with a ruler, tell time to the nearest five minutes, and count coins up to a dollar.
Count coins from a jar and ask how much is there. Read clocks together at breakfast and bedtime. Measure something around the house with a ruler. These small habits build the exact skills students practice in class.
Ask the student to draw a picture or use small objects like coins or buttons to act it out. Have them say what they know and what they need to find. The drawing matters more than getting the answer fast.
Yes. By the end of the year, students should know sums like 7 plus 8 or 6 plus 9 from memory, without counting on fingers. Short, daily practice with flashcards or quick games works better than long sessions.
Build hundreds, tens, and ones first with base-ten blocks before moving to written addition and subtraction within 1000. Skip-counting by 5s, 10s, and 100s reinforces the structure. Save regrouping across hundreds for later in the year once students are solid with tens.
Two-step word problems and subtraction with regrouping are the common sticking points. Telling time to five minutes also takes longer than expected, especially quarter past and quarter to. Plan to revisit these across the year rather than teaching them once.
Measurement is a good place to practice addition and subtraction within 100 in a real context. Number lines used for length also support mental math with tens and hundreds. Plan measurement units near related computation work so the two reinforce each other.
A student is ready when they can add and subtract two-digit numbers without counting, read and write numbers up to 1000, tell time on an analog clock, and solve simple money problems. If any of these feel shaky, practice a few minutes most days over the summer.