Writing · Free lesson
IELTS Task 1: from, to and by in data changes
A correct number with the wrong preposition can report the wrong result. This short IELTS Academic Writing Task 1 skill keeps the endpoints and difference separate.
Professor Scott MendozaThe short answer
From gives the starting value, to gives the final value, and by gives the size of the change. If membership rises from 120 to 180, it rises by 60 members—not by 180.
To is where the value ends. By is how much it changes.
Original practice data: the club had 120 members in 2022 and 180 in 2023. You can write Membership rose from 120 to 180, or Membership rose by 60 members. Both describe the same change. Combining them is also possible: Membership rose by 60 members, from 120 to 180. These two observations do not show whether the increase was steady during the year.
Compare the examples
Membership rose from 120 to 180.
Membership rose by 60 members.
Membership rose by 60 members, from 120 to 180.
Rose to 60 says the final value was 60. Rose by 60 says the increase was 60. They are different claims, even though the number is the same.
Build the meaning step by step
Find both endpoints
from 120 to 180
Calculate the difference
180 − 120 = 60
Match the preposition to its job
rose by 60 members
Try it now
Keep the values in the right roles
Read all answers and explanations
Library visits increased from 200 to 260. Choose the accurate final-value sentence.
Visits increased to 260.To 260 gives the final count. The increase was 60, not 260.
Applications fell from 90 to 70. Complete: Applications fell ___ 20.
byThe fall is 90 − 70 = 20. By gives that amount; the final value remains 70.
A chart counts bicycles: 40 in 2022, 55 in 2023. Which sentence keeps both the change and unit?
The number rose by 15 bicycles.55 − 40 =15 bicycles. It is an absolute count, not a 15 percent increase.
Put it into practice
Repair the change sentence
Original practice data: the number of classes fell from 48 in 2022 to 36 in 2023. Report the decrease and final value accurately.
The number of classes fell by 36 to 12.
See a model answer
The number of classes fell by 12, from 48 to 36.
Both parts now describe the same change. The sentence does not invent a cause for it.
A little more clarity
Common questions
A few useful details before you move on.
Does by also work with a decrease?
Yes. Use by for the size of a fall and to for the final value. Keep the downward verb.
Attendance fell by 10 people, from 80 to 70.
Must every sentence include from, to and by?
No. Use the detail needed for a clear description. From...to can show the change without separately stating by, provided the values and units are clear.
Attendance rose from 80 to 100 people.
Take it into your day
Keep endpoints with from/to and the amount of increase or decrease with by.
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