Bridging Hundreds and Thousands: Add and Subtract

Slide 1

Year 5 Mathematics Learning to cross number boundaries with confidence

Slide 2

What is Bridging?

Moving across number boundaries Like crossing a bridge from one hundred to the next Helps us add and subtract larger numbers Makes mental math easier and faster

Slide 3

Think About This...

What happens when you count from 99 to 101? What about from 999 to 1001? How do the digits change?

Slide 4

Bridging When Adding - Hundreds

Start with: 67 + 45 Break it down: 67 + 33 + 12 Bridge to 100 first: 67 + 33 = 100 Then add the rest: 100 + 12 = 112

Slide 5

Let's Try Together!

Work out: 78 + 36 First, how much to get to 100? 78 + ? = 100 Then add the rest!

Slide 6

Bridging When Adding - Thousands

Example: 867 + 245 Break it down: 867 + 133 + 112 Bridge to 1000: 867 + 133 = 1000 Add the rest: 1000 + 112 = 1112

Slide 7

Bridging When Subtracting - Hundreds

Start with: 124 - 38 Break it down: 124 - 24 - 14 Bridge down to 100: 124 - 24 = 100 Subtract the rest: 100 - 14 = 86

Slide 8

Addition vs Subtraction Bridging

{"left":"Addition: 78 + 36\nBreak apart to reach next hundred\n78 + 22 + 14 = 100 + 14 = 114","right":"Subtraction: 124 - 38\nBreak apart to reach previous hundred\n124 - 24 - 14 = 100 - 14 = 86"}