Carbon Dioxide: o2c
Water: h2o
Oxygen: o2
Water is h2o because there are 2 hydrogen molecules and 1 oxygen molecule.
h2 = 2 hydrogen molecules
o = 1 oxygen molecule
She took 7 boxes of carrots and 9 boxes of potatoes home.
75 boxes of carrots - 68 boxes of carrots = 7 boxes of carrots.
80 boxes of potatoes - 71 boxes of potatoes = 9 boxes of potatoes.
|3+10|=|3|+|10|
|13|=|13|
13=13