addition
14 + 7
21
18-9
9
sum
the answer to an addition problem
what is area
the amount of tiles or squares in a space
the arrangement of objects in rows and columns
array
29+4
33
56-3
53
difference
the answer to a subtraction problem
area of a 3 by 4 array
12 square units
to show or model
represent
45 + 67
112
84-19
65
vertical
writing up and down
45
34
what is the area of a 2 rows and 5 in each row array?
10 square units
adding the number of objects in a row
repeated addition
135+24
159
173-28
145
horizontal
writing side by side
23+67
what do you count first, rows or number in each row?
row
perfect square
when there are the same number of items in the rows as there are rows For example 3 by 3
how do you check an addition problem answer
with subtraction
206-47
159
which direction do rows go?
columns?
rows go side to side
columns go up and down
what direction do rows go?
horizontal
orientation
changing the way an array looks (vertical to horizontal)