Addition Table
Subtraction
Rounding
Word Problems
Random
100
Complete the table
100
What place value do you need to start at when subtracting? Why?
Ones place or smallest place value position. If you don't start there, you'll have trouble if there's regrouping
100
Why do we round?
To estimate problems, to check your work or see if an answer makes sense
100
Kohei had 8 books in his seat sack. He checked out 3 more from the library and then returned 5. How many does he have now? Show your work or explain.
8 + 3 = 11
11-5 = 6
6 books
100
Solve 479 + 345 using expanded form.
400 + 70 + 9
300 + 40 + 5
700 + 110 + 14
810 + 14 = 824
200
What happens when you move down the addition table?
You add one more
200
Solve 458 - 245
213
200
Round 248 to the nearest ten and hundred. Explain.
ten- 250, because it's only 2 away from 250, but 8 away from 240
hundred- 200, because it's 48 from 200 and 52 from 300
200
Dylan found 12 pencils on the ground. He already had 4 rows of 4 pencils in his pencil case. How many does he have now? Show or explain.
12 + (4 x 4)
12 + 16 = 28 pencils
200
Isaac wrote 8 words per sentence for his paragraph. He then erased 2 words. How many words does he have left?
What information are you missing?
How many sentences he first wrote.
300
What happens when you move across the addition table (either direction)
You add or subtract one
300
Solve 652 - 365
287
300
Round 29 to the nearest ten and hundred. Explain
ten- 30, because it's only 1 away from 30
hundred- 0, because it's closer to 0 than 100
300
We have two weeks of winter vacation Dora read 2 books every day during vacation. Then, she read 29 more in January. How many books did she read altogether? Show or explain.
2 weeks = 14 days
14 x 2 (or 14 + 14) = 28
28 + 29 = 57 books
300
Isaac wrote 8 words per sentence for his paragraph. He wrote 6 sentences. He then erased 2 words. How many words does he have left? Write or show your work.
(8 x 6) - 2 = w
48 - 2 = 46 words
400
What happens when you move diagonal in the addition table? Write a few examples.
The number stays the same, like 4+1= 5 and 3+2=5 OR
the number adds two, like 4, 6, 8, 10
400
Solve 854 - 796 using expanded form
800 + 50 + 4
700 + 90 + 6
= 58
400
Round 396 to the nearest hundred and ten. Why are they the same?
400, because 400 is also a multiple of 10 and 396 is closer to 400 than 300
400
Nevin, Maquela, and Juliette colored during quiet time. Nevin and Juliette had 3 rows of 5 colored pencils together. Maquela had 2 rows of 3 colored pencils. When it was time to clean up, Juliette put away 11 colored pencils. How many were left? Show or explain.
(3 x 5) + (2 x 3) - 11 = p
15 + 6 - 11 = p
21 - 11 = 10 pencils left
400
There are 400 seats in the auditorium. For the music concert, 127 parents and 68 students need seats. About how many seats will be empty? Show or explain.
About 200 seats, because 130 + 70 = 200 and
400 - 200 = 200
500
What other patterns do you notice in the table? Show or explain
Answers vary
500
Solve 500 - 348
Explain how you subtracted the ones and tens place.
152
Ones- Can't do 0-8, so had to go to the hundreds place to borrow one hundred. Then borrowed one ten from tens place and 10-8=2
Tens- Can't do 0-4, got 10 tens that turned into 9 tens
500
Look at the expression 547 - 448.
Round to estimate the difference, then solve and see if your answer makes sense.
Rounding: 550-450=100
Difference: 99, yes that makes sense because it's very close to 100
500
Cameron, Lia, and O'Riah made a tower. It was 10 blocks high and 6 blocks wide. Esther and Sephora built a tower that was 8 blocks high and 2 blocks wide. How many blocks did they use altogether? Write an equation with a variable, then solve.
(10 x 6) + (8 x 2) = b
60 + 16 = b
76 = b
500
There are 400 seats in the auditorium. For the music concert, 127 parents and 68 students need seats. Will there be more or less than 200 seats empty? How do you know?
More, because we rounded 127 and 68 up to subtract from 400.