How can you verify the result of 143 + 305 * 70 using a calculator or long multiplication?
Executive summary
You can verify 143 + 305 × 70 by applying the standard order of operations (multiply then add): 305 × 70 = 21,350, then 21,350 + 143 = 21,493. Available sources in the provided search results discuss calculators and date tools but do not mention this specific arithmetic example; the search set contains general online calculator pages (e.g., timeanddate’s date tool) rather than a worked numeric verification (available sources do not mention this arithmetic calculation) [1].
1. Multiply first, then add — basic procedure
The arithmetic verification starts with the rule that multiplication precedes addition. Compute 305 × 70 first: 305 × 7 = 2,135, then append the zero from ×70 to get 21,350; finally add 143 to reach 21,493. The search results include multiple general calculator pages and tools that perform arithmetic and date calculations (for example, timeanddate’s date-adder tool), but none of them show this exact calculation step-by-step (available sources do not mention the stepwise numeric example; see p1_s3) [1].
2. How a basic calculator confirms it
On a simple electronic or smartphone calculator you can enter the sequence: 305 × 70 = (gives 21,350), then + 143 = (gives 21,493). Many online math and utility sites host basic calculators you can use to check arithmetic; for instance, calculator.net maintains general math calculator pages you can use to perform those keystrokes [2]. The provided search results document the existence of such online calculator tools but do not display this exact calculation [2].
3. How to verify with long multiplication and long addition
Long-multiplication: multiply 305 by 70 by treating 70 as 7 tens. Multiply 305 × 7 = 2,135; write that as 21,350 because of the trailing zero. Then perform long addition: 21,350 + 143 = 21,493 (units: 0+3=3; tens:5+4=9; hundreds:3+1=4; thousands:2+0=2). The search results catalogue various online calculation tools (date calculators, percent calculators) that demonstrate using arithmetic in applied tools, but they do not supply this explicit long-multiplication example (available sources do not mention this worked long-multiplication instance) [3] [4] [5].
4. Cross-check methods and why they matter
Double-check by reversing operations or using modular checks: compute (305 × 70) mod 10 gives 0, then add 143 gives units digit 3 — matches 21,493. Or compute 305 × 70 = 21,350 and 143 separately; adding them is straightforward. The supplied search results point to general-purpose calculators and date tools where such modular or repeated checks could be carried out but they do not discuss modular-check techniques for this arithmetic specifically (available sources do not mention modular-check guidance for this problem; [3]0).
5. Practical suggestions for tools to use
Use any standard calculator app (phone, computer, or online) or an online math calculator page such as the general math calculators indexed by calculator.net [2]. For teaching or demonstration, write the long multiplication and long addition on paper to show each carry and place-value step; the search results include multiple online calculator and date tools but are not instructional pages for this particular arithmetic demonstration [2] [1].
Limitations and source note: the provided search results are largely focused on date calculators and general math calculator listings [3] [4] [1] [2]. None of the supplied sources include a worked example of 143 + 305 × 70 or an explicit step-by-step verification of that numeric result; therefore the arithmetic steps and final total reported above are not quoted from these sources but are standard arithmetic procedures (available sources do not mention the exact calculation) [3] [1] [2].