To multiply two 2-digit numbers that have the same ¿ rst digits and last digits that sum to 10, multiply the ¿ rst digit by the next higher digit, then attach the product of the last digits in the original two numbers. Example: 84 × 86 ĺ 8 × 9 = 72 and 4 × 6 = 24; answer: 7224.
If you want to change selection, open document below and click on "Move attachment"
- (no access) - Secrets of Mental Math (guidebook).pdf, p12
|status||not read|| ||reprioritisations|
|last reprioritisation on|| ||suggested re-reading day|
|started reading on|| ||finished reading on|