Addition Trick
Do the following addition problem by saying aloud the partial sums.
Start with 1000.
Add 40 to it.
Now add another 1000.
Now add 30.
Add another 1000.
Now add 20.
Now add another 1000.
Now add 10.
What is the total?
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No, it is not 5,000!
The sum is 4,100.
(Check your place value)
4,090 + 10 = 4,100.