Unit 5 Review

Place Value

100

What is the value of the digit 7 in the number 4,782?

700

200

In the number 5,634, what digit is in the hundreds place?

6

300

Write the number 2,410 in expanded form.

2,000+400+10

400

What is the place value of the 9 in the number 9,856?

9,000

500

Explain how you would find the value of the digit 3 in the number 3,245.

It is in the thousands place, so I know that it is 3,000

Rounding

100

Round 67 to the nearest ten.

70

200

What is 342 rounded to the nearest hundred?

300

300

Round 85 to the nearest ten.

90

400

If you round 1,234 to the nearest hundred, what do you get?

1,200

500

Explain how you would round the number 4,678 to the nearest thousand.

You would look at the thousands place and then look at the number behind if it is bigger than five; you round the thousands place up. If it is smaller than five, you keep the number in the thousands place the same. Every number after the thousands becomes a 0

Standard Algorithm Adding

100

What is the sum of 23 and 45 using the standard algorithm?

68

200

Add 156 and 289 using the standard algorithm.

445

300

 What do you get when you add 4,752 and 1,289 using the standard algorithm?

6,041

400

Calculate 3,567 + 2,456 using the standard algorithm.

6,023

500

Explain the steps in the standard algorithm for addition.

• Line up the digits: Write the numbers one under the other, making sure the digits are lined up by place value (ones, tens, hundreds, etc.). For example:

   456
  + 789
•  ------
  
  
  
  
  

• Start from the right (ones place): Begin with the rightmost column (ones place). Add the digits in this column together.

  • Example: 6 + 9 = 15.

  • Write the 5 in the ones place of the answer, and carry the 1 (because 15 is more than 10) to the next column.

• Move to the next column (tens place): Now, add the digits in the tens column, along with any carry-over from the previous step.

  • Example: 5 + 8 = 13, plus the 1 we carried over gives us 14.

  • Write the 4 in the tens place, and carry the 1 over to the next column.

• Move to the hundreds place: Add the digits in the hundreds column, including any carry-over from the tens column.

  • Example: 4 + 7 = 11, plus the 1 we carried over gives us 12.

  • Write the 2 in the hundreds place and carry the 1 to the next column (though there is no next column here).

• Write the final answer: After adding all the columns, write down the carry-over (if any) in front of the sum.

  • The sum of 456 + 789 is 1245.

Standard Algorithm Subtraction

100

What is the difference when you subtract 15 from 45 using the standard algorithm?

30

200

Subtract 132 from 250 using the standard algorithm.

118

300

Find the result of 1,500 - 678 using the standard algorithm.

822

400

What do you get when you calculate 5,432 - 2,345 using the standard algorithm?

3,087

500

 Describe the steps in the standard algorithm for subtraction.

• Line up the numbers: Write the two numbers one under the other, making sure the digits are lined up by place value (ones, tens, hundreds, etc.). For example:

  
  

   784
  - 296
• ------
  
  

• Start from the right (ones place): Begin with the rightmost column (the ones place). Look at the top number and subtract the bottom number.

  • Example: 4 - 6. Since 4 is smaller than 6, you need to borrow from the next column.

• Borrow if needed: If the number on top is smaller than the number on the bottom, borrow from the next place value to the left (tens, hundreds, etc.).

  • Example: In the tens place, you have an 8. Borrow 1 from the 8, turning it into a 7, and make the 4 in the ones place become 14.

• Subtract: Now, subtract the bottom number from the top number.

  • Example: 14 - 6 = 8.

• Move to the next column (tens place): Now that you've taken care of the ones place, move to the tens place. If you borrowed earlier, subtract the number in the tens place of the bottom number from the new top number.

  • Example: 7 - 9. Since 7 is smaller than 9, you need to borrow again, this time from the hundreds place.

  • Borrow 1 from the 7 in the hundreds place, turning the 7 into 6 and the 7 in the tens place into 17.

• Subtract again: Now subtract the bottom number from the top number.

  • Example: 17 - 9 = 8.

• Move to the next column (hundreds place): Finally, subtract the bottom number in the hundreds place from the top number.

  • Example: 6 - 2 = 4.

• Write the final answer: After subtracting each column, write the final answer below the line.

  • The subtraction of 784 - 296 is 488.

Story Problems

100

If Sam has 15 apples and buys 7 more, how many apples does he have now?

22 apples

200

Lisa had 50 candies, and she gave away 23. How many does she have left?

27 candies

300

A box contains 120 toys, and 45 are taken out. How many toys remain in the box?

75 toys

400

You buy three books: one costs $12, the other book costs $15, and the last one costs $18. How much did you spend?

$45

500

John has $100. He spends $37 on a toy and $25 on a game. How much money does he have left?

$38