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Left-to-Right Algorithm for Subtraction. Created by Paula Cantera Elk Neck Elementary. The Left-to-Right Algorithm for Subtraction builds on a skill most people use every day -- reading from left to right. First, some vocabulary. minuend. 857. (top number). subtrahend.
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Left-to-Right Algorithm for Subtraction Created by Paula Cantera Elk Neck Elementary
The Left-to-Right Algorithm for Subtraction builds on a skill most people use every day -- reading from left to right.
First, some vocabulary. minuend 857 (top number) subtrahend (bottom number) - 469 difference 388 (the answer)
Let’s begin. First think of the subtrahend (the bottom number)in expanded form - like this… 857 - 469 400 + 60 + 9
857 - 469 400 + 60 + 9 857 - 400 Now subtract the hundreds. 457
857 - 469 400 + 60 + 9 857 - 400 457 - 60 Next subtract the tens. 397
857 - + + 400 60 9 469 857 - 400 457 - 60 8 17 397 Finally subtract the ones. - 9 388
857 - + + 400 60 9 469 857 - 400 457 - 60 8 17 397 - 9 388 is the difference! 388
Let’s try another one that might be a bit harder. Are you up for the challenge?
5642 - 1076 Expanded form 1000 + 0 + 70 + 6 or 1000 + 70 + 6 ***ALERT*** Notice that there are no hundreds in the number The number can be expanded in either of the two ways shown above.
5642 - 1076 1000 + 70 + 6 5642 - 1000 Subtract the thousands. 5 14 4642 - 70 Subtract the tens. 6 12 4572 - 6 Subtract the ones. 4566 4566 is the difference!
The Left-to-Right Algorithm for Subtraction is just one more way to subtract multi-digit numbers. Go ahead! Give it a try! It might just become your favorite!