3-Digit Addition
Find the sum:
548+125
673
Find the difference:
527-215
312
Ms. Fegan was solving a puzzle. On Monday, she put together 254 pieces. On Tuesday, she put together 147 pieces. On Wednesday, Cooper knocked over some of the puzzle and she lost 123 pieces. How many pieces are still left on the table?
Step 1: 254+147=401
Step 2: 401-123=278
Ms. Fegan has 278 pieces remaining on the table.
Even+Even =?
Even
A student is solving 250+135 using partial sums. The student’s work is below.
200+100=300
50+30=80
0+5=5
300+80+5=380
The student made a mistake.
• Use place value language to describe the student’s error.
• Correctly solve the equation.
• Use pictures, models, numbers, or words to support your answer
The student did not add the partial sums correctly. They forgot to add the ones. The correct answer is 385.
Find the sum:
159+647
806
Find the difference:
954-267
687
Step 1: 364+557=921
Step 2: 921-143=778
Mrs. Powell has 778 berries to take home.
Odd+Odd=?
Even
A student is solving 458+169 using partial sums. The student’s work is below.
400+100=500
50+60=110
8+9=17
500+110+17=607
The student made a mistake.
• Use place value language to describe the student’s error.
• Correctly solve the equation.
• Use pictures, models, numbers, or words to support your answer
The student did not add the partial sums correctly. The correct answer is 627.
Benji collects coins from other continents. He has 264 coins from Europe and 372 coins from South America. How many coins does he have altogether?
Benji has 636 coins altogether.
Hector is reading a book with 542 pages. He has already read 299 pages. How many pages are left?
Hector has 243 pages left in his book.
Ms. Appleton is baking cookies for her friend's baby shower. She makes 232 chocolate chip cookies and 491 M&M cookies. The people at the party loved the cookies so much. They ate a total of 565 cookies. How many cookies were left over?
Step 1: 232+491=723
Step 2: 723-565=158
Ms. Appleton has 158 cookies left over.
Even+Odd=?
Odd
A student is solving 321+154 using partial sums. The student’s work is below.
300+100=400
20+50=60
1+4=5
400+60+5=465
The student made a mistake.
• Use place value language to describe the student’s error.
• Correctly solve the equation.
• Use pictures, models, numbers, or words to support your answer
The student did not add the tens correctly. The correct answer is 475.
Esteban was practing guitar after school. He practiced for 124 minutes during week 1 and 368 minutes during week 2. How many total minutes did Esteban practice altogether?
Coco is creating a lego set of a castle that has 732 pieces. He has already placed 396 pieces. How many pieces are left?
Coco has 336 pieces left in his lego set.
Mrs. Les was playing games at the Alley Oops Arcade. She won 526 tickets on skeeball. Then, she won another 347 tickets on speedracer. She wants to get a stuffed animal from the gift shop for 355 tickets. How many tickets does she have left to spend?
Step 1: 526+347=873
Step 2: 873-255=518
Mrs. Les has 518 tickets left to spend.
Does Even+Odd=Even?
No
A student is solving 578+124 using partial sums. The student’s work is below.
500+100=600
70+20=90
8+4=12
600+90+12=602
The student made a mistake.
• Use place value language to describe the student’s error.
• Correctly solve the equation.
• Use pictures, models, numbers, or words to support your answer
The student did not add the partial sums correctly. The correct answer is 702.
A student is using partial sums to solve the following problem: 254+658. Their work can be found below:
200+600=800
50+50=100
4+8=12
800+100+12= 902
The student made a mistake. Describe the student's error and correct their mistake.
The student's mistake was they forgot to add the tens place of the 12. This caused the answer to be 10 less than the correct answer. 800+100+12=912.
How can you decompose to solve 648-351?
648-300=348
348-50=298
298-1=297
Ms. Heldt gets 682 fiction books and 297 non-fiction books for her classroom library. During the week, students check out 356 books. What set of equations could be used to find out how many books were left in her classroom library?
Step 1: _______+______=_______
Step 2: ________-_______=_______
Step 1: 682+297=979
Step 2: 979-356=623
Does Odd+Odd=Even?
Yes
A student is solving 170+150 using partial sums. The student’s work is below.
100+100=200
70+50=120
0+0=0
200+120+0=3200
The student made a mistake.
• Use place value language to describe the student’s error.
• Correctly solve the equation.
• Use pictures, models, numbers, or words to support your answer
The student did not add the partial sums correctly. They added an extra 0. The answer is 320.