Grade by Grade
B. Number · Operations: Adding and Subtracting to 1000, Multiplying and Dividing

Operations: Adding and Subtracting to 1000, Multiplying and Dividing: Unit Review

A1 B2.1 B2.2 B2.3 B2.4 B2.5 B2.6 B2.7 B2.8 B2.9About 40 minutes
Learning goals
  • I can add and subtract numbers up to 1000 and check my answer.
  • I can multiply and divide using arrays, equal groups and facts I know.
  • I can solve story problems and explain my thinking.
  • I can work with groups of fractions and with ratios of 1 to 2, 1 to 5 and 1 to 10.

Words to know

algorithm
A set of steps that always works, like the column method.
regroup (trade)
Swap 10 ones for 1 ten, or 10 tens for 1 hundred, and back.
estimate
A smart guess that is close to the exact answer.
product
The answer when you multiply.
fact family
Related facts that use the same three numbers, like 3 × 6 = 18 and 18 ÷ 3 = 6.
ratio
A comparison using "for every", like 2 wheels for every 1 bike.

Let's review!

In this unit you became a much stronger math thinker. You used mental math and estimation with numbers up to 1000, added and subtracted with the column method, solved story problems, learned to multiply and divide with arrays, learned your facts of 2, 5 and 10, worked with groups of fractions, and used ratios to scale up. This review has a few questions from every lesson. Try each one, then press Show answer to check. If a part feels tricky, go back to that lesson for more practice.

Mental Math: Adding and Subtracting to 1000

1

640 + 300 = ?

2

299 + 154 = ?

3

500 − 470 = ?

Estimating Sums and Differences to 1000

1

Round 762 to the closest hundred.

2

Estimate 391 + 412.

3

Eli says 702 − 289 = 513. Use an estimate to check.

Adding to 1000: From Blocks to the Column Method

1

356 + 227 = ?

2

478 + 365 = ?

3

In the column method, what does a carried 1 in the hundreds column stand for?

Subtracting within 1000: From Blocks to the Column Method

1

563 − 241 = ?

2

624 − 358 = ?

3

800 − 436 = ?

Whole book: 512 pagesRead: 278Left: ?
A bar model for the question about Nora's book below. The whole is 512 pages. One part is the 278 pages she read. The missing part is the pages left.

Solving Addition and Subtraction Problems to 1000

1

A rink sold 385 tickets on Friday and 447 on Saturday. How many tickets in all?

2

Some birds were at a feeder. 125 flew away. 275 stayed. How many were there at first?

3

A book has 512 pages. Nora has read 278. How many pages are left?

4

Max has $600. He spends $245 on a bike and $120 on a helmet. How much is left?

5 in each rowrow 1row 2row 3row 4
An array with 4 rows of 5. Use it for the first question below.

Multiplication: The × Sign and Arrays

1

Write a multiplication sentence for 4 rows of 5.

2

3 × 9 = ?

3

Is 6 × 4 the same as 4 × 6? What is the product?

Division: Sharing, Grouping and Fact Families

1

30 ÷ 5 = ?

2

21 kids make teams of 3. How many teams?

3

Write the fact family for 4, 9 and 36.

Multiplication Rules: Any Order, Ones, Zeros and Splitting

1

1 × 63 = ? and 63 × 0 = ?

2

2 × 8 × 5 = ?

3

Use splitting to solve 7 × 6.

Multiplication and Division Facts of 2, 5 and 10

1

5 × 9 = ?

2

2 × 7 = ? and 14 ÷ 2 = ?

3

How many dimes make 80¢?

Solving Multiplication and Division Problems

1

A bookshelf has 5 shelves with 8 books on each. How many books?

2

24 muffins are shared equally on 4 plates. How many on each plate?

3

Zoe has 3 shells. Ben has 5 times as many. How many shells does Ben have?

Groups of Halves, Thirds and Fourths

1

1/4 + 1/4 + 1/4 = ?

2

8 kids each eat 1/2 of a sandwich. How many whole sandwiches?

3

Write 3/3 as a repeated addition. Is it more, less or the same as 1 whole?

Ratios: Scaling Up by 2, 5 and 10

1

For every 1 bike there are 2 wheels. How many wheels on 9 bikes?

2

How many cents are 7 nickels worth?

3

Fill in the 1 to 10 table: 1 → 10, 4 → □, □ → 90.

Just for fun

Why is the equal sign so humble?

Because it knows it is not greater than or less than anyone!

How to use this review

  • Do the review over two or three short sittings. Each section matches one lesson.
  • Let your child use tools: base-ten blocks or straw bundles, counters, coins, paper strips, a number line or drawings. Using tools is part of Grade 3 math.
  • Estimate first for adding and subtracting questions, and check with the opposite operation.
  • After each answer, ask "How did you know?" Explaining matters as much as the answer.
  • Note which section had mistakes, then revisit that lesson's examples, activity and practice.
Check your understanding

Quiz

1.

What is 458 + 200?

2.

What is the best estimate for 596 + 311?

3.

What is 367 + 285?

4.

What is 603 − 275?

5.

A school had 720 books. It gave away 250 and then got 130 new ones. How many books does it have now?

6.

What is 4 × 7?

7.

What is 36 ÷ 4?

8.

What is 0 × 15?

9.

1/3 + 1/3 = ?

10.

For every 1 hand there are 5 fingers. How many fingers on 8 hands?

For parents and teachers

Use mistakes to choose what to revisit. Each review section matches one lesson.

  • Changes the wrong digit (640 + 300 = 670), or fixes a friendly number the wrong way: revisit Mental Math: Adding and Subtracting to 1000.
  • Rounds to the wrong place, or doesn't notice an answer that is far off: revisit Estimating Sums and Differences to 1000.
  • Forgets to carry, writes two digits in one column, or misaligns digits: revisit Adding to 1000: From Blocks to the Column Method with blocks or straw bundles.
  • Takes the smaller digit from the bigger in each column, or gets stuck with zeros (800 − 436): revisit Subtracting within 1000: From Blocks to the Column Method.
  • Adds every number in a story, stops after one step, or gets stuck on start-missing problems: revisit Solving Addition and Subtraction Problems to 1000 and draw bar models.
  • Adds the factors (4 × 5 = 9), or can't build an array: revisit Multiplication: The × Sign and Arrays.
  • Shares unequally, writes division backwards, or can't write a fact family: revisit Division: Sharing, Grouping and Fact Families.
  • Thinks 63 × 0 = 63 or 1 × 63 = 1, or can't split a hard fact: revisit Multiplication Rules: Any Order, Ones, Zeros and Splitting.
  • Slow or unsure with 2, 5 and 10 facts: revisit Multiplication and Division Facts of 2, 5 and 10 and play the fact flip game daily.
  • Can't tell when to multiply or divide, or misses "times as many": revisit Solving Multiplication and Division Problems.
  • Adds the bottom numbers (1/3 + 1/3 = 2/6), or can't count halves into wholes: revisit Groups of Halves, Thirds and Fourths with paper strips.
  • Adds instead of scaling up (8 hands have 13 fingers), or reverses a ratio: revisit Ratios: Scaling Up by 2, 5 and 10.

A few mistakes are normal. Praise the strategy your child explains, not only the right answer.