The polygon has 4 sides, so it is a quadrilateral.
- Look at the polygon. Count its sides one by one.
- This polygon has 4 sides.
- A polygon with 4 sides is called a quadrilateral. So the answer is Quadrilateral.
Math for 2nd graders is about numbers up to 1,000 and adding and subtracting them. Your child learns what the hundreds, tens and ones digits mean, adds and subtracts within 100 quickly and works up to 1,000 with blocks and drawings. Measuring length with a ruler is the other big topic. Time, money, graphs and shapes fill out the year. A child who finishes 2nd grade solid in place value and addition facts starts 3rd grade ready for multiplication.
The one-minute check
Ask your child, without paper or counters: "What is 10 more than 47? What is 10 less than 47?"
If they get it
Your child says 57 and 37 within a few seconds, without counting. That means tens and ones from 1st grade are solid, and 2nd grade has something to build on.
If they do not
Your child counts 48, 49, 50 and on, one number at a time, or answers 48 and 46. That is the gap, and it comes from 1st grade.
Most of 2nd grade is built on tens and ones: three-digit numbers, adding and subtracting within 1,000 and finding 10 or 100 more in one step. A child who counts by ones gets slow and loses track as the numbers grow, even when each new idea makes sense.
Read each line as "my child can…". Confident checks are strengths; hesitations are where to look closer.
Not every topic weighs the same. Place value, adding and subtracting, word problems and measuring length are where most of 2nd grade goes, and they are what 3rd grade builds on. Time, money, graphs, odd and even numbers and shapes are real topics, but a smaller share of the year.
The center of 2nd grade. Your child learns that the digits of a number like 706 mean 7 hundreds, 0 tens and 6 ones, and that 100 is a bundle of ten tens.
Comes from last year: First grade taught that a two-digit number is tens and ones, and that 10 is a bundle of ten ones. A child who still sees 47 as "a 4 and a 7" has nothing to build hundreds on.
2.NBT.1 · 2.NBT.2 · 2.NBT.3 · 2.NBT.4
Your child adds and subtracts two-digit numbers quickly, then moves to three-digit numbers with blocks and drawings. This is where regrouping comes in: trading 10 ones for a ten, or a ten for 10 ones.
Comes from last year: First grade added a two-digit number to a one-digit number or to a multiple of 10, such as 34 + 20. A child who still counts by ones to add 34 + 20 will find 2nd grade numbers too big to count.
2.NBT.5 · 2.NBT.6 · 2.NBT.7 · 2.NBT.8 · 2.NBT.9
By the end of 2nd grade, your child should know every sum of two one-digit numbers by heart, such as 8 + 7 = 15, and subtract within 20 quickly.
Comes from last year: First grade made facts within 10 quick and taught strategies for facts up to 20. A child who still counts on fingers for 6 + 3 needs those first.
2.OA.2
Story problems with adding and subtracting within 100, in one or two steps. The missing number can be the start, the change or the end. A missing start is the hardest kind.
Comes from last year: First grade solved the same kinds of story problems within 20. A child who adds the two numbers in every story, whatever the story says, has learned to hunt for numbers instead of reading.
2.OA.1
Your child measures with a ruler, a yardstick, a meter stick and a measuring tape, in inches, feet, centimeters and meters, and solves story problems about length.
Comes from last year: First grade measured by laying paper clips or cubes end to end, with no gaps and no overlaps. A child who skipped that step reads a ruler as a list of numbers, not as a row of equal units.
2.MD.1 · 2.MD.2 · 2.MD.3 · 2.MD.4 · 2.MD.5 · 2.MD.6
Your child tells time to the nearest five minutes and uses a.m. and p.m. Money comes in too, with story problems about bills and coins.
Comes from last year: First grade told time to the hour and half hour. Money is new in 2nd grade, and it leans on skip-counting by 5s and 10s from earlier in the year.
2.MD.7 · 2.MD.8
Picture graphs and bar graphs with up to four categories, plus line plots of lengths your child has measured.
Comes from last year: First grade sorted data into up to three categories and asked "how many more?" Comparing two bars is a subtraction problem, so slow subtraction slows graphs too.
2.MD.9 · 2.MD.10
The first steps toward multiplication. Your child sorts groups of up to 20 objects into odd and even, and counts objects set out in rows and columns.
Comes from last year: First grade facts include doubles such as 6 + 6 and 7 + 7. An even number is a double, so a child who knows doubles already has the idea.
2.OA.3 · 2.OA.4
Your child names and draws shapes by their sides and corners, splits a rectangle into rows of equal squares and cuts shapes into halves, thirds and fourths.
Comes from last year: First grade cut circles and rectangles into halves and fourths. Thirds are new this year, and so is the idea that two halves can have different shapes.
2.G.1 · 2.G.2 · 2.G.3
These are the Common Core standards for 2nd grade math. Each link opens a page that explains the topic in simple words, with examples, the usual sticking points and four practice questions.
| Area | What schools teach | Share of the year |
|---|---|---|
| Place value to 1,000 | The center of 2nd grade. Your child learns that the digits of a number like 706 mean 7 hundreds, 0 tens and 6 ones, and that 100 is a bundle of ten tens. | Major |
| Adding and subtracting to 1,000 | Your child adds and subtracts two-digit numbers quickly, then moves to three-digit numbers with blocks and drawings. This is where regrouping comes in: trading 10 ones for a ten, or a ten for 10 ones. | Major |
| Addition and subtraction facts | By the end of 2nd grade, your child should know every sum of two one-digit numbers by heart, such as 8 + 7 = 15, and subtract within 20 quickly. | Major |
| Word problems | Story problems with adding and subtracting within 100, in one or two steps. The missing number can be the start, the change or the end. A missing start is the hardest kind. | Major |
| Measuring length | Your child measures with a ruler, a yardstick, a meter stick and a measuring tape, in inches, feet, centimeters and meters, and solves story problems about length. | Major |
| Time and money | Your child tells time to the nearest five minutes and uses a.m. and p.m. Money comes in too, with story problems about bills and coins. | Smaller |
| Graphs and line plots | Picture graphs and bar graphs with up to four categories, plus line plots of lengths your child has measured. | Smaller |
| Odd, even and equal groups | The first steps toward multiplication. Your child sorts groups of up to 20 objects into odd and even, and counts objects set out in rows and columns. | Smaller |
| Shapes and equal shares | Your child names and draws shapes by their sides and corners, splits a rectangle into rows of equal squares and cuts shapes into halves, thirds and fourths. | Smaller |
Five real problems from our 2nd grade bank. Work through them with your child, check each answer, and see the steps for any problem.
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Problem 1
The polygon has 4 sides, so it is a quadrilateral.
Problem 2
The park bench is 1 meter long, and Maya said 2 meters. The correct statement is: "The park bench is one meter shorter than Maya says."
Problem 3
The number is 132. The model shows 1 hundred (100), 3 tens (30), and 2 ones (2), and .
Problem 4
Ava has 23 books. Subtract: .
Problem 5
There are 20 squares in the rectangle. You can find this by counting 4 squares in each row, for 5 rows: .
These are not careless mistakes. Each one is a rule that worked perfectly well until this year, applied consistently to a place where it no longer holds, which is why the same wrong answer keeps coming back. Recognising the specific rule is far more useful than more practice.
Writes "three hundred six" as 3006 or as 36.
The number is written the way it sounds: 300, then 6. The 0 in 306 shows that there are no tens. With three-digit numbers, a zero in the middle is easy to drop.
Works out 52 - 17 and gets 45.
In each column the smaller digit is taken from the bigger one (7 - 2 and 5 - 1). The 52 needs a ten broken into 10 ones first, which gives 12 - 7 = 5 ones and 35 in all.
Says a crayon is 7 inches long because it ends at the 7, when it starts at the 1.
The numbers on a ruler get read like counting numbers. Length is the number of spaces between the marks, so a crayon from 1 to 7 is 6 inches long.
Reads a clock with the minute hand on the 4 as 4 minutes past the hour.
The numbers on a clock face count hours. For minutes, each number stands for 5 more, so the 4 means 20 minutes past.
Schools vary, but most 2nd grade classrooms move in about this order. Useful if you are trying to work out whether something is genuinely behind or simply has not been taught yet.
Next year does not re-teach these. It starts from them, which is why a gap left open over the summer tends to show up in October rather than in June.
Free 2nd grade math quick check
Ten questions on the year’s main topics, about 10 to 15 minutes, with a worked solution for every one. Take it online or print it with the answer key.
Start the quick check →
Place value to 1,000, addition and subtraction facts within 20, adding and subtracting within 100 and then 1,000, word problems, measuring length, time, money, graphs, odd and even numbers, arrays and shapes. Place value and adding and subtracting carry the most weight.
For addition, yes. By the end of 2nd grade, the Common Core expects children to know every sum of two one-digit numbers from memory, such as 8 + 7 = 15. Subtraction within 20 should be quick too, often by thinking of the matching sum: 15 - 8 = 7 because 8 + 7 = 15.
Start with the one-minute "10 more, 10 less" check on this page. For a broader read, try the free 10-question quick check. The Level Up assessment, about 30 to 40 questions on a computer or tablet, adapts to each answer and shows where your child stands, including gaps from earlier grades. It is included in the free trial.