Subtraction Techniques with Base Ten Blocks

What is the first step in solving the subtraction problem 45 - 17?

• Regroup the tens into ones

• Subtract the tens place

• Line up the numbers vertically

• Subtract the ones place

Why do we need to regroup in the subtraction problem 45 - 17?

• Because there are more ones in 17 than in 45

• To make the numbers easier to subtract

• Because it's a standard procedure in all subtraction problems

• To increase the value of the tens place

What do we do after regrouping in the subtraction problem?

• Subtract the tens place

• Add the ones place

• Multiply the tens place

• Subtract the ones place

How many units are left in the ones place after subtraction in the problem 45 - 17?

• 5 units

• 10 units

• 8 units

• 7 units

What concept is used to solve the subtraction problem when there are not enough ones?

• Addition

• Division

• Regrouping

• Multiplication

How many rods are left after regrouping in the problem 45 - 17?

• Five rods

• Two rods

• Three rods

• Four rods

What is the final step in solving the subtraction problem 45 - 17?

• Multiply the tens place

• Add the ones place

• Subtract the tens place

• Regroup the ones into tens

What is the result of 45 - 17?

• 27

• 28

• 26

• 29