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## Subtracting Friendly Numbers

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**Subtracting Friendly Numbers**by Grade 4**Friendly Numbers**are numbers that have 9’s in the Ones like 39or 59 Tens like 199or 399 Hundreds like 3999or 6999**We can change numbers into**so that they are easier to subtract in our heads! Friendly Numbers Follow this simple rule: You can change numbers if they: Are close to a ten, hundredor thousand**305**305-6=299(a friendly number) - 297 297-6 = to become 291 299 - 291 8 Now subtract**202 -3 =199 (a friendly number)**202 144 144 -3 becomes 141 199 141 5 8 Now subtract**509**509-10= 499(a friendly number) - 386 386 -10 becomes 376 499 - 376 2 3 1 Now subtract**Friendly Subtraction can also have**Numbers WITH 0’S As a Second number**such as 200, 50, 800**Why? They are easier to subtract! That’s why!**482**+ 5 = 487 - 295 + 5 = 300 487 - 300 1 8 7 Now subtract**841**- 3 = 838 - 303 - 3 = 300 838 - 300 5 3 8 Now subtract!**831**Subtract 8 = 823 - 508 Subtract 8= 500 823 - 500 2 3 3 Now subtract!**2000**Minus 1 to become 1999 - 2 01 Minus 1 to become 200 1999 - 200 9 9 1 7 Now subtract!**805**Add 2 to become 807 - 598 Add 2 to become 600 807 - 600 2 0 7 Now subtract!**4000**Subtract 1to become 3999 - 2495 Subtract 1to become 2494 3999 - 2494 1 5 0 5 Now subtract!**The End – now do your own in your scribbler on the next**slide! Check them when you’re done all of them.**Now do these on your own paper:**1. 800 - 599 (799 - 598=201) 2. 3000 - 213 (2999 - 212=2787) 3. 4876- 2999 (4877 - 3000 =1877) 4. 5226 - 3796 (5230 - 3800=1470) Did you find the mistake?