Once can roughly round to tens if the numbers are less than 1000, or to hundreds if the numbers are less than 10000, etc., trying to make up for large round-off errors which occur when the number are close to 1/2 the round-off amount.
E.G Add: 13+ 57+ 49 + 45 + 78 + 105
Add 10 + 60 +50 + 50 + 80 + 100
One way is to do front end estimation!
xxx=2x
distributive property
To give a reason to something,(numbers, sums, differences, or problems you usle hear the word reasonablein a map scale problem like me
Well, 1 is equal to 1. 9 is equal to 9. So any number from 0 to 9. I do not think this is what is meant by the question. If you mean any number with more than one digit. There is no such number. Because 11 sums to 2. 19 sums to 10. 21 sums to 3. 29 sums to 11. 111 sums 3. 119 sums to 11. The sums do not grow as fast the increase of digits.
In the same way as you estimate them for whole numbers.
The basic idea is the same as when you estimate sums and differences of larger numbers (which may or may not be integers). You round the numbers to one or two decimal digits, then add them up.
One way is to do front end estimation!
0.7 + 0.9 = 1.6 0.7 - 0.9 = -0.2
When you do not require an exact answer but an approximation is sufficient.
150 - 4000 - 600 = -4450
xxx=2x
you have to add
Alike is the same as Differences means subtractions Sums means additions Quotients means divisions Products means multiplications
distributive property
I think you round it to the nearest whole number...
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