content questions
practice problems
story problems
check your work
base-10
100

How do we know when to regroup?

If the bottom is bigger, you better borrow!

100

75-21=

54

100

Ford and his sister have 50 cars total. If Ford has 27 cars, how many cars does his sister have?

50-27=23 cars

100

35-21=14

21+14=35

100

60-24=

36

200
How do you regroup?

You borrow from the tens to give to the one's.

200

46-19=

27

200

Lively had 67 butterflies, but 30 flew away. How many butterflies does she have left?

67-30=37 butterflies

200

70-25=45

45+25=70

200

48-35=

13

300

How would you change this number to regroup?

73 (how many tens? how many one's?)

6 tens 

13 one's

300

68-33=

35

300

Millie has 77 crayons and Charlotte has 59. How many more crayons does Millie have?

77-59=18 crayons

300

85-4=81

81+4=85

300

22-17=

5

400

What does 'subtract' mean?

to take away

400

42-27=

15

400

Hudson had 74 dollars but Matthew took away 27 dollars. How many dollars does Hudson have left?

74-47=47 dollars

400

64-37=27

37+27=64

400

82-33=

49

500

What is the answer to a subtraction problem called?

the difference

500

70-38=

32

500

Bear had 91 cookies and he gave Noah 45 cookies. How many cookies does Bear have left?

91-45=46 cookies

500

83-24=59

24+59=83

500

90-25=

65