What is 5 thousand + 7 thousand in standard form

5000 + 7000 = 12,000 or twelve thousand

the law of definite proportions states samples of a compound will always contain the same proportion of elements by mass. in other words, a given compound will always contain the same elements in the same proportions by mass.the law of multiple proportions states when two elements combine with each other to form more than one compound, then the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.

1200 inches = 30 yards12 inches= 1 foot3 feet= 1 yard3feet= 36 inchesyou can set up a proportion then use inverse operations that looks sorry it looks so sloppy lol