800
The closest estimate is the exact value.39*2 = (40 - 1)*2 = 80 - 2 = 78Then 39*22 = 39*2*11 = 78*11 = 858[Multiplication by 11 give the digits 7, 7+8 and 8 - with the carry overs applied to the answer.]
Round 38 to 40. Estimate the product as 80. The actual product is 76.
Product of 22 percent of some number is 0.22 * the number.
22 = 2 x 11
That's an overestimate.
The answer is 8.
underestimate
20 x 8 = 160
8 x 6000 = 48000
1/5 x 8/9
22
32.
80 x 8000 = 640000
About 25.3 miles per hour. A good estimate is to multiply your total knots by 1.15 (representing miles) your product is an estimated answer.
Let x = the number 8x - 10 = 22
There is no best estimate (other than the exact answer) since more effort will always produce a better estimate.25*32 = 25*4*8 = 100*8 = 800.
This is how I approximate the product: 32 * 8 = 30*8 + 2*8 = 10(3*8) + 16 = 10(24) + 16 = 240 + 16 = 256.