Adding fractions that share the same denominator by adding the numerators and keeping the denominator.
If you have 52 of a pie and get 51 more, you now have 53—same size pieces, just count them up.
Showing a random 20 of 50 problems.
Example 1
medium
113+11?=1110. Find the missing numerator.The result bar must reach 10 out of 11. How many more pieces (shown as ?) must the middle bar have?
Example 2
challenge
For positive integer n, simplify n1+n2+n3+⋯+nn in closed form.
Example 3
easy
A bowl has 104 kg of rice. You add 103 kg more. How much rice is in the bowl?
Example 4
medium
Add 92+94+91.
Example 5
medium
Express 204+206 in lowest terms.
Example 6
easy
Add 61+64.One sixth plus four sixths fills five of the six equal parts in the result bar.
Example 7
challenge
Express 81+81+81+81 as a single fraction and as a decimal.
Example 8
medium
Find the missing numerator: 134+13□=1311.
Example 9
medium
Add 85+87 and write the result as a mixed number.
Example 10
medium
Two ribbons are 83 m and 84 m. What is their total length?Each bar represents one metre split into 8 equal sections. Joining the two ribbons fills 7 of those sections.
Example 11
medium
Add 283+187.
Example 12
hard
Bag A has 125 kg of flour, bag B has 127 kg, bag C has 1211 kg. Total mass?
Example 13
easy
Worked example: add 62+63 and show why the denominator does not change.
Example 14
medium
Compute 2011+2013 and write as a mixed number.
Example 15
medium
Add 154+156 and simplify.Ten of 15 parts shaded in the sum bar reduces to 2/3 after dividing numerator and denominator by 5.
Example 16
hard
Find all positive integers n≤10 such that 12n+12n simplifies to a unit fraction k1.
Example 17
easy
True or false: 103+102=205.
Example 18
easy
Add 41+41.Two fourths fill exactly half the bar, showing why 2/4 simplifies to 1/2.
Example 19
challenge
If 12a+12b=129 and a=2b, find a and b.
Example 20
easy
A jug contains 72 litre of water. You pour in another 73 litre. How much water is in the jug?The jug starts with 2 seventh-parts and gains 3 more, for a total of 5 out of 7.