Adding and subtracting within 1,000

Problem types

• Add within 1000
• Subtract within 1000
• Add two totals, then take away a part

Builds on

• Regrouping within 1,000
• Explaining why a strategy works · Earlier idea

  A strategy works because breaking a number by place, and trading 10 ones for 1 ten, keep the amount the same. The same reasons make quick addition and subtraction within 1000 work.

• Adding or subtracting 10 or 100 mentally · Useful idea

  Adding or subtracting tens and hundreds mentally is the first step in adding and subtracting three-digit numbers.

Leads to

• Adding and subtracting whole numbers
• Equal equations with the four operations
• Fluent decimal arithmetic · Extend the idea

  Adding and subtracting thousands by place value extends to decimal sums, where like places are added and regrouped.

• Income tax, budgets, and net worth · See it applied

  A net worth statement adds assets and subtracts debts in the thousands.

Related skills

None listed.