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This video is going to be looking at the addition and subtraction of numbers in standard form to start with we're going to look at numbers which have the same power of 10 the most important thing when having a question with addition subtraction of numbers in standard form is don't convert them to ordinary numbers keep them in standard form if you convert them to ordinary numbers and back again you may get the correct answer but you won't get any marks this is our first question two point three seven times ten to the three plus four point six five times ten to the three the one thing you must remember when adding or subtracting numbers in standard form is you can only add or subtract if the powers of ten are the same in this case both are times ten to the three they are the same we can add those numbers together quite easily I'm going to write them one under the other because that's how I do my additions so I'm going to write them as two point three seven times ten to the three plus four point six five times 10 to the three there the powers of ten are the same so I'm going to add them together and whatever I get is going to be times 10 to that 3 so this is two point three seven plus four point six five that comes to 7.0 two times 10 to the 3 quite easy the second example six point zero five times 10 to the 6 plus seven point six seven times 10 to the six again the powers of 10 are the same they're both 10 to the 6 so I can add them together and I'm going to get something times 10 to the 6 and if I add together six point zero five and seven point six seven I'm going to get 13 point seven two times 10 to the 6 however 13 is not a number between 1 and 10 so this is actually not in standard form before I submit my answer I've got to convert this to standard form which means instead of thirteen point seven two it's actually got to be one point three seven two what I've done here is I've made this first part a power of ten smaller so to keep the whole number the same size I've got to make the second part a power of ten bigger so instead of 10 to the sixth it's going to become ten to the seven and that's my answer in this next question I've got matching powers of ten so I want and it's a subtraction so I'm going to do two point two five times ten to the four take away the six point four three times ten to the four both are 10 to the four so when I subtract I'm going to get a times ten to the four and if I do 2.25 takeaway 6.43 I'm going to get minus four point one eight times 10 to the four and that's my final answer this next question it's a subtraction again but this time the numbers are very close together so if I perform the subtraction it's going to be seven point three six times ten to the five take away six point two six five times ten to the five a same powers of ten both 10 to the fifth so my answer is going to be times 10 to the fifth but if I perform the subtraction seven point three six takeaway six point six five I get naught point seven...