First write all of the compounds/atoms in either side then fill in existing values and balance
Na- 1
Br- 1
Ca- 1
Cl- 2
Na- 1
Cl- 1
Ca-1
Br-2
Balance to get
2NaBr+CaCl2=2NaCl+CaBr2
There are three subatomic particles known: (1) electron which is found outside the nucleus of an atom and (2 and 3) protons and neutrons which are both inside the nucleus. As they are outside the nucleus, it is easier to transport electron than any other subatomic particle. Thus, atom and its ion differ in the number of electrons.
So to balance an equation, you need to get the same amount of each type of element on either side of the --> . So you pretty much are given the subscripts in the equations and you need to add coefficients (just normal numbers) in front of any formula that needs it, keeping anything balance.

turns into

These coefficient numbers are the molar ratios, so 2 moles of KCl3 for every 3 moles of O2 so 1. 3:2
Then you can use these ratios of find out how many moles of one thing are needed if you are given the amount of another.

and use cross multiplication to solve for whatever you don't know
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5. is your answer thank you!