What’s the Sum of 2 5 and 2 4

Figurer Apply

Estimate sums and differences for positive proper fractions, n/d (numerator/denominator), where n ≤ d and 0 ≤ n/d ≤ i. Use rounding to estimate answers when adding or subtracting proper fractions.

Estimating Fractions by Rounding

This online reckoner was originally set up to judge by rounding fractions to the nearest i/ii. Fractions were rounded to 0, 1/2 or i. For more than precise estimating we added the ability to round fractions to the closest 1/4 or 1/8. See the section on “Value of Estimating Fractions” below.

Estimating sums and differences of fractions to the nearest one/2

• Fractions < 1/4 are rounded down to 0
• Fractions ≥ one/iv and ≤ three/4 are rounded to one/2
• Fractions > 3/4 are rounded up to 1

Estimating sums and differences of fractions to the nearest one/4

• Fractions < one/8 are rounded down to 0
• Fractions ≥ one/8 and < 3/viii are rounded to 2/eight=1/4
• Fractions ≥ 3/8 and < 5/8 are rounded to four/eight=2/4=ane/ii
• Fractions ≥ five/8 and < 7/8 are rounded to 6/8=three/4
• Fractions ≥ 7/8 are rounded up to 8/8=one

Estimating sums and differences of fractions to the nearest 1/8

• Fractions < 1/sixteen are rounded down to 0
• Fractions ≥ 1/16 and < three/16 are rounded to 2/sixteen=i/8
• Fractions ≥ 3/xvi and < five/xvi are rounded to four/sixteen=ii/8=i/four
• Fractions ≥ 5/16 and < 7/16 are rounded to 6/16=3/8
• Fractions ≥ seven/16 and < ix/16 are rounded to 8/16=four/8=1/ii
• Fractions ≥ fifteen/xvi are rounded up to 16/xvi=8/8=1

Fractions table for halves, quarters, eighths and sixteenths with decimal equivalents

See our expanded fractions table.

Value of Estimating Fractions

First, e’er follow the guidelines your instructor gives you lot for estimating sums and differences of fractions.

Estimating operations on proper fractions in this way is sometimes more accurately done by a human being than a reckoner. A figurer can certainly make an estimate based on divers parameters in a formula and there are many applications where estimating is done very well with calculators (or computers). In this case however, a better approximate might be achieved by a human.

For example, the standard exercise for estimating sums and differences of fractions for grammar school students seems to exist rounding to the closest ane/2 by rounding to 0, 1/2 or 1. This works well through a computer such every bit if you are adding 3/8 + xi/16. 3/eight is closest to one/2 and xi/16 is less than iii/4 so it is besides closest to one/2. Estimating, we accept 1/ii + 1/2 = one. If nosotros really add these terms 3/8 + 11/16, with a common denominator of 16 nosotros have six/16 + eleven/16 = 17/xvi = 1 + one/sixteen which is really close to our gauge of 1. If we now effort 1/8 + three/4, by the rules for rounding to the closest ane/two, 1/8 is closest to 0 and iii/4 is rounded to 1/2. Estimating we go 0 + one/2 = one/2. However, the real answer is 1/8 + 3/four = 1/viii + 6/eight = 7/8. This is much closer to 1 than information technology is to one/2 and then our gauge is not very authentic. Keep in listen that an approximate, by definition, is a

rough

adding.

If yous try to add several fractions by the same method such equally i/8 + ane/xvi + ii/viii + 3/16 yous tin can end up with an estimate that is very crude. Therefore, you lot should apply good judgment in your estimating process.

For these and some more basic methods of working with fractions see as well Assist With Fractions.