Vocabulary
The digit that shows how many ones are in a number.
Ones digit
Use a hundred chart to find 64 + 22. Explain your work.
64 + 22 = 86
Start at 64, move down 2, move to the right 2. The sum is 86.
Use an open number line to find 13 + 82. Explain your work.
13 + 82 = 95
Start at 13 on the number line. Jump by 10s eight times. Jump by 1 two times. The sum is 95.
Use the break apart strategy to find 19 + 73. Explain your work.
19 can be broken into 10 and 9. 73 can be broken into 70 and 3.
10 + 70 = 80
9 + 3 = 12
80 + 12 = 92
Use the compensation strategy to find 88 + 11. Explain your work.
88 + 2 = 90
11 - 2 = 9
90 + 9 = 99
The digit that shows how many groups of 10 are in a number.
Tens digit
Use a hundred chart to find 47 + 51. Explain your work.
47 + 51 = 98
Start at 47, move down 5, move to the right 1. The sum is 98.
Use an open number line to find 29 + 9. Explain your work.
29 + 9 = 38
Start the number line at 29, jump by 1 nine times. The sum is 38.
Use the break apart strategy to solve 66 + 30. Explain your work.
66 can be broken into 60 and 6. We won't break apart 30 because it is already 3 tens.
60 + 30 = 90
90 + 6 = 96
Use the compensation strategy to find 14 + 67. Explain you work.
14 + 6 = 20
67 - 6 = 61
20 + 61 = 81
A tool that can help you add or subtract. It can begin at any number.
Open number line
Jayden has 12 Among Us stickers. Eric gives him 29 Among Us stickers. How many stickers does Jayden have in all? Use a hundred chart and explain your work.
12 + 29 = 41
Start at 12, move down 2, move to the right 9. Jayden has 41 Among Us stickers.
Ryan has 49 Pokemon cards. Jihoo has 42 more cards than Ryan. How many Pokemon cards does Jihoo have? Use an open number line and explain your work.
49 + 42 = 91
Start at 49 on the number line, jump by 10s four times, jumps by 1s two times. The sum in 91 Pokemon cards.
Sean brought 55 pieces of candy for Halloween. Ace brought 24 more pieces of candy than Sean. How many pieces of candy did Ace bring? Use the break apart strategy and explain your work.
55 can be broken into 50 and 5. 24 can be broken into 20 and 4.
50 + 20 = 70
5 + 4 = 9
70 + 9 = 79 pieces of candy
Robin visited Daiso and bought 16 new pencils. His friend Simon also visited Daiso and bought 18 new erasers. How many school supplies did they buy in all? Use the compensation strategy and explain your work.
16 + 4 = 20
18 - 4 = 14
20 + 14 = 34 school supplies
A mental math strategy where you break the number into its place value part.
Break apart
Juah has 15 marshmallows to share with her friends. Her mom gave her 23 more marshmallows to share with Ms. Stephanie and Ms. Christa's classes. How many marshmallows does Juah have in all? Use a hundred chart and explain your work.
15 + 23 = 38
Start at 15, move down 2, move to the right 3. Juah has 38 marshmallows.
Stella went to Everland and went on 12 rides. Her friend Sophia also went to Everland and rode 17 more rides than Stella. How many rides did Sophia go on? Use an open number line and explain your work.
12 +17 = 29
Start on 12 on the number line, jump by 10s one time, jump by 1s seven times. The sum is 29 rides.
Haya wants to decorate the classroom in rainbows. She drew 62 rainbows. Her friend Nishanth wanted to help her and drew 8 rainbows. How many rainbows did Haya and Nishanth draw in all? Use break apart method and explain your work.
62 can be broken into 60 and 2. 8 will stay the same.
2 + 8 = 10
60 + 10 = 70 rainbows
For next week's science experiment, G2P has 34 cups of water and 9 cups of corn starch. How many cups of ingredients do they have in all? Use the compensation method and explain your work.
34 + 6 = 40
9 - 6 = 3
40 + 3 = 43 cups of ingredients
Math you do in your head.
Mental math
Ms. Megan awarded 10 Dojo points to Liam, 16 Dojo points to Summer, and 21 Dojo points to Eileen on Monday. How many Dojo points did Ms. Megan award in all? Use a hundred chart and explain your work.
10 + 16 + 21 = 47 Dojo points
Start at 10, move down 1, move to the right 6. Now you are at 26. From 26, move down 2, move to the right 1. The sum is 47 Dojo points.
Last week, Mr. Deal had 24 counseling meetings with students. This week, he has 31 more counseling meetings. How many meetings does he have in all? Use an open number line and explain your work.
24 + 31 = 55
Start at 24, jump by 10s three times, jump by 1s one time. The sum is 55 counseling meetings.
Ms. Yuna bought notebooks for Grade 1, Grade 2 and Grade 3 students. She bought 38 notebooks for Grade 1, 30 notebooks for Grade 2, and 15 notebooks for Grade 3. How many notebooks did Ms. Yuna buy in all?
38 notebooks can be broken into 30 and 8. 30 will stay 30. 15 notebooks can be broken into 10 and 5.
30 + 30 + 10 = 70
8 + 5 = 13
70 + 13 = 83 notebooks
Ms. Megan was planning the Class Dojo Store, and she purchased 25 Haribo snacks and 32 stamps. How many items did Ms. Megan purchase in all? Use compensation strategy and explain your work.
25 + 5 = 30
32 - 5 = 27
30 + 27 = 57 items