2.7 Adding and Subtracting within 1,000

Select all representations of the number 318.

A:

B:

C: \(300 + 10 + 8\)

D: \(100 + 30 + 8\)

E: Three hundred eighteen

F: Three hundred eighty-one

Write a number for each representation.

1. Five hundred twenty-seven

   ______________

2. \(300+60+8\)

   ______________

3.  

   

   

   ______________

4. \(5 + 40 + 700\)

   ______________

Find the value of each sum or difference. Show your thinking.

1. \(52 - 43\)
2. \(65 - 19\)
3. \(36 + 47\)

Find the value of each difference.

1. \(77 - 10\)
2. \(77 - 20\)
3. \(90 - 70\)

Find the value of each difference. Show your thinking.

1. \(53 - 50\)
2. \(285 - 281\)
3. \(90 - 88\)

1. Here are Kiran's blocks.

   

   

   He gives 2 tens to Priya.

   What is the value of Kiran's blocks now? Show your thinking.

2. Then Priya gives Kiran 4 hundreds.

   What is the value of Kiran's blocks now? Show your thinking.

Find the value of each difference. Show your thinking. Use a number line or base-ten blocks if it helps.

1. \(648 - 25\)

2. \(535 - 24\)

1. Find the value of \(600 - 289\). Show your thinking.
2. Find the value of \(245 + 612\). Show your thinking.

Find the value of each expression. Explain your reasoning.

1. \(365 + 214\)
2. \(365 - 214\)

Here is Han's work finding the value of a difference.

1. What difference did Han find? Show your reasoning.
2. Write an addition and a subtraction equation that match Han's work.

Tyler says he can find the value of \(438 - 275\) using what he knows about differences of two-digit numbers.

“First I find \(43 - 27\) and then I find \(8 - 5\) and that gives me the answer.”

Use Tyler's reasoning to find the value of \(438 - 275\).

Find the value of each sum. Show your thinking.

1. \(238 + 52\)
2. \(252 + 38\)
3. \(119 +61\)

Find the value of each sum. Explain your reasoning.

1. \(395 + 77\)
2. \(417 + 532\)

Find the value of each sum. Show your thinking.

1. \(238 + 54\)
2. \(345 + 77\)

Here is how Jada found the value of \(741 + 179\).

\(741 + 9 = 750\)

\(750 + 100 = 850\)

1. Explain Jada's error.
2. Correct Jada's work and find the value of \(741 + 179\).

1. Find the value of \(382 + 479\).

2. Find the missing digit that makes the equation true. Explain how you know.

   \(534 + 4 \underline{\hspace{.5cm}} 6 = 1,\!000\)

Here is how Han likes to add.

1. Explain why Han's method works.
2. What do you think of Han's method?
3. Use Han's method to find the value of \(388 + 259\).

Here is an equation with several digits missing.

\(\underline{\hspace{.5cm}} \ \underline{\hspace{.5cm}}5 + 63 \underline{\hspace{.5cm}} = 823\)

1. What digits can you put in the blanks to make the equation true?
2. Can you complete the numbers in more than one way to make the equation true?

1. Find the value of each difference.

   \(325 - 19\)

   \(437 - 115\)

2. Jada drew this picture to find the value of a difference. What difference did Jada calculate? Explain how you know.

   

   

Find the value of each difference. Show your thinking.

1. \(936 - 428\)

2. \(352 - 181\)

Jada is finding the value of \(571 - 385\). She says that she can take the ones from the ones, tens from the tens, and hundreds from the hundreds, with no decomposing. Do you agree with Jada? Explain your reasoning.

Find the value of each difference. Show your thinking.

1. \(216 - 88\)
2. \(803 - 564\)

Find the value of each difference in a way that makes sense to you. Show your thinking.

1. \(747 - 295\)
2. \(811 - 255\)
3. \(600 - 378\)

Here is how Kiran found the value of \(543 - 276\)

\(500 - 200 = 300\)

\(300 - 30 = 270\)

\(270 - 3 = 267\)

1. Explain why Kiran's method works.
2. Use Kiran's method to find \(325 - 276.\)

1. Choose a three-digit number so that subtracting by place value is a good strategy for finding the value of \(637 - \boxed{\phantom{8}} \boxed{\phantom{8}} \boxed{\phantom{8}}\). Explain your reasoning and find the value of the difference.
2. Choose a three-digit number so that adding on to the smaller number is a good strategy for finding the value of \(637 - \boxed{\phantom{8}} \boxed{\phantom{8}} \boxed{\phantom{8}}\). Explain your reasoning and find the value of the difference.
3. Choose a three-digit number so that decomposing two different units is a good strategy for finding the value of \(637 - \boxed{\phantom{8}} \boxed{\phantom{8}} \boxed{\phantom{8}}\). Explain your reasoning and find the value of the difference.