A. Changes in numbers and quantities

During the five years 2010–2015, internet use across the world was estimated to have increased twofold¹, while in China, it quadrupled². In the developing world, internet use grew by a factor of³ three.

The drastic⁴ changes in interest rates resulted in a threefold⁵ increase in the number of people unable to keep up their mortgage repayments.

The estimated number of stars in the Milky Way has been revised upwards⁶ in light of recent discoveries.

The weather patterns have deviated from the norm⁷ in recent years.

Sales fluctuate⁸ from month to month.

Interest rates have seesawed⁹ all year.

Share prices have been erratic¹⁰ this last month.

• ¹ the suffix –fold means ‘multiplied by that number’
• ² increased by four times
• ³ multiplied by
• ⁴ severe and sudden
• ⁵ twofold, threefold, etc.; can be used as an adverb or adjective
• ⁶ changed to a higher number
• ⁷ moved away from the standard or accepted pattern
• ⁸ keep going up and down
• ⁹ gone up and down at regular intervals
• ¹⁰ not regular and often changing suddenly

B. More expressions for describing statistics and numbers

• When the different amounts were added up, the aggregate was £600,000. [total]
• I’ve aggregated all the figures. [added up all the different amounts]
• The Finance Minister said the July rise in inflation was only a blip. [temporary change]
• There seems to be a correlation between mathematical and musical ability. [connection between facts or things which cause or affect each other]
• The percentage of GDP expenditure which goes on education varies considerably from country to country. [Gross Domestic Product: total output of a country]
• There’s a discrepancy between our figures and yours. [difference between two things that should be the same]
• The ratio of men to women in the Engineering Faculty was 3 to 1. [relationship between two amounts]
• The company’s figures were found to be flawed and the accountant was fired. [inaccurate]
• She suffered multiple injuries in the accident. [very many of the same type]
• Our data are inconsistent with yours. [not in agreement with]

C. Assessing quantity

Let me give you a ballpark figure of how much money we expect to make this year. If I tot up everything, we begin to run into six figures³. There are a lot of variables⁴ and our projected figures may not be all that accurate. So I’ve erred on the side of caution⁶ and I’ve rounded things down⁷ rather than up, in order to give you a conservative⁸ estimate.

• ¹ guess believed to be accurate
• ² add everything up (less formal)
• ³ get a figure over 100,000
• ⁴ different factors that may change
• ⁶ been cautious
• ⁷ make an estimate
• ⁸ cautious