Or

## Subtracting numbers under 20 from numbers under 100

• Subtracting numbers under 20 from numbers under 100
• Course: Mathematics
• Section: Subtraction
• Outcome: Two digit subtraction - Problem Solving
• Activity Type: Printable
• Activity ID: 3680

## Testimonials

“What a brilliant site you have!!! I love it, especially as it saves me hours and hours of hard work. Others who haven't found your site yet don't know what they are missing!”
Patricia Celikbilek, Teacher

### Awarded June 2012 “Best Educational Website for Teaching and Learning”

#### United Kingdom – National Curriculum expand/collapse

• ##### KS2.Ma2 – Number and algebra
• Knowledge, skills and understanding

• Solving numerical problems

• KS2.Ma2.4 – Pupils should be taught to:

• KS2.Ma2.4.a – Choose, use and combine any of the four number operations to solve word problems involving numbers in 'real life', money or measures of length, mass, capacity or time, then perimeter and area

• Using and applying number

• KS2.Ma2.1 – Pupils should be taught to:

• Problem solving

• KS2.Ma2.1.a – Make connections in mathematics and appreciate the need to use numerical skills and knowledge when solving problems in other parts of the mathematics curriculum

• Calculations

• KS2.Ma2.3 – Pupils should be taught to:

• Number operations and the relationships between them

• KS2.Ma2.3.a – Develop further their understanding of the four number operations and the relationships between them including inverses; use the related vocabulary; choose suitable number operations to solve a given problem, and recognise similar problems to which they apply

• Mental methods

• KS2.Ma2.3.e – Work out what they need to add to any two-digit number to make 100, then add or subtract any pair of two-digit whole numbers; handle particular cases of three-digit and four-digit additions and subtractions by using compensation or other methods [for example, 3000 - 1997, 4560 + 998]

• Written methods

• KS2.Ma2.3.i – Use written methods to add and subtract positive integers less than 1000, then up to 10000, then add and subtract numbers involving decimals; use approximations and other strategies to check that their answers are reasonable

#### Australia – Australian Curriculum expand/collapse

• ##### Number and Algebra
• Number and place value

• ACMNA055 – Recall addition facts for single-digit numbers and related subtraction facts to develop increasingly efficient mental strategies for computation

#### New Zealand – National Standards expand/collapse

• ##### 5.NA – Number and algebra
• 5.NA.1 – Apply additive and simple multiplicative strategies and knowledge of symmetry to:

• 5.NA.1.a – Combine or partition whole numbers

• ##### 6.NA – Number and algebra
• 6.NA.1 – Apply additive and simple multiplicative strategies flexibly to:

• 6.NA.1.a – Combine or partition whole numbers, including performing mixed operations and using addition and subtraction as inverse operations

#### United States – Common Core State Standards expand/collapse

• ##### 2.NBT – Number & Operations in Base Ten
• Mathematics

• 2.NBT.5 – Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.

• ##### 3.OA – Operations & Algebraic Thinking
• Mathematics

• 3.OA.8 – Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding. (This standard is limited to problems posed with whole numbers and having whole-number answers; students should know how to perform operations in the conventional order when there are no parentheses to specify a particular order.)

• ##### 3.NBT – Number & Operations in Base Ten
• Mathematics

• 3.NBT.2 – Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.

• ##### 4.NBT – Number & Operations in Base Ten (Grade 4 expectations in this domain are limited to whole numbers less than or equal to 1,000,000.)
• Mathematics

• 4.NBT.4 – Fluently add and subtract multi-digit whole numbers using the standard algorithm.