Subtracting
40-20
20
How many tens would I draw for the equation 23+20
4 tens, 2 for 23 and 2 for 20.
47+11
58
19+13
32
71+21
92
70-30
40
When I added 15 + 14, I got 9 ones and 2 tens, do I need to make a 10? Why or why not?
You don't need to make 10 because the sum of the ones place is less than 10.
33+55
88
24+19
43
25+25
50
51-20
31
My sister added 45+25 =60. Is she correct? If not, what did she forget to do?
She is incorrect. She forgot to make a 1 ten when she added the ones. 5+5 =10, she just wrote the 0.
45+12
57
68+27
95
49+18
67
65-50
I added 23+26= 29. How do you know this is wrong? What steps did I miss? What sum would make this equation true?
You forgot to add the tens. The answer should be 49.
63+36
99
47+47
94
68+32
100
78-31
47
If I added 79+23, would I need to make a 10? If so, why?
Yes, you would need to make a 10 because 9+3=12 which is larger than 10.
28+71
99
82+29
111
86+28
114