xxx=2x
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
distributive property
The two different pairs of decimals whose sums are 14.1 and one pair involves regrouping on math are 8.4 and 5.7.
use mental math
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.
In the same way as you estimate them for whole numbers.
I think you round it to the nearest whole number...
It means to give the reason of something, (numbers,sums,differences, and problems.)
0.7 + 0.9 = 1.6 0.7 - 0.9 = -0.2
it means round to the nearest 100 ten or 1s
When you do not require an exact answer but an approximation is sufficient.
150 - 4000 - 600 = -4450
xxx=2x
calculator Your brain.
you have to add
Alike is the same as Differences means subtractions Sums means additions Quotients means divisions Products means multiplications